The primary risk with using open source software in a commercial software construction is license agreements requiring release of modified code. Open source software is software that uses publicly available source code, which can be seen, modified, and distributed by anyone. Open source software has some advantages, such as being affordable and flexible, but it also has some disadvantages, such as being potentially insecure or unsupported.

One of the main disadvantages of using open source software in a commercial software construction is the license agreements that govern the use and distribution of the open source software. License agreements are legal contracts that specify the rights and obligations of the parties involved in the software, such as the original authors, the developers, and the users. License agreements can vary in terms of their terms and conditions, such as the scope, the duration, or the fees of the software.

Some of the common types of license agreements for open source software are:

Permissive licenses: license agreements that allow the developers and users to freely use, modify, and distribute the open source software, with minimal or no restrictions. Examples of permissive licenses are the MIT License, the Apache License, or the BSD License.

Copyleft licenses: license agreements that require the developers and users to share and distribute the open source software and any modifications or derivatives of it, under the same or compatible license terms and conditions. Examples of copyleft licenses are the GNU General Public License (GPL), the GNU Lesser General Public License (LGPL), or the Mozilla Public License (MPL).

Mixed licenses: license agreements that combine the elements of permissive and copyleft licenses, and may apply different license terms and conditions to different parts or components of the open source software. Examples of mixed licenses are the Eclipse Public License (EPL), the Common Development and Distribution License (CDDL), or the GNU Affero General Public License (AGPL).

The primary risk with using open source software in a commercial software construction is license agreements requiring release of modified code, which are usually associated with copyleft licenses. This means that if a commercial software construction uses or incorporates open source software that is licensed under a copyleft license, then it must also release its own source code and any modifications or derivatives of it, under the same or compatible copyleft license. This can pose a significant risk for the commercial software construction, as it may lose its competitive advantage, intellectual property, or revenue, by disclosing its source code and allowing others to use, modify, or distribute it.

The other options are not the primary risks with using open source software in a commercial software construction, but rather secondary or minor risks that may or may not apply to the open source software. Lack of software documentation is a secondary risk with using open source software in a commercial software construction, as it may affect the quality, usability, or maintainability of the open source software, but it does not necessarily affect the rights or obligations of the commercial software construction. Expiration of the license agreement is a minor risk with using open source software in a commercial software construction, as it may affect the availability or continuity of the open source software, but it is unlikely to happen, as most open source software licenses are perpetual or indefinite. Costs associated with support of the software is a secondary risk with using open source software in a commercial software construction, as it may affect the reliability, security, or performance of the open source software, but it can be mitigated or avoided by choosing the open source software that has adequate or alternative support options.