A constraint is a restriction or limitation that affects the performance or value of a solution1. Constraints can be related to time, cost, quality, scope, resources, or technology2. In this question, option A is a valid constraint because it specifies a time limit for the solution implementation. Options B, C, and D are not constraints, but rather objectives or goals that the solution should achieve or support.

References: The answer is based on the BABOK® Guide, which is a key resource for the CCBA® certification. Specifically, it relates to the Strategy Analysis knowledge area, where defining solution scope and business case is a key task for the BA13. It also relates to the Requirements Analysis and Design Definition knowledge area, where the BA should define design options and recommend a solution14.

1: Certification of Capability in Business Analysis™ (CCBA®) Handbook 2: Business Analysis Expert Certification, CCBA® | IIBA® 3: Certification of Capability in Business Analysis™ (CCBA®) 4: The Ultimate Guide to Business Capability Analysis