CSI’s MasterFormat® (2004 and later editions) organizes work results into five major groups, several of which are broken into subgroups. In CDT and CSI materials, the key subgroups are described as follows:

Facility Construction Subgroup (Divisions 02–19) – Covers sitework and building construction elements, such as existing conditions, concrete, masonry, metals, wood, finishes, openings, specialties, equipment, furnishings, conveying systems, fire suppression, plumbing, HVAC (in early editions), and electrical (in divisions 26–28 pre–2010 structure; in more recent updates MEP is consolidated differently but still under “facility services”).

Facility Services Subgroup (Divisions 20–29) – Specifically established to organize mechanical, electrical, plumbing, fire suppression, communications, and related systems—collectively termed facility services.

Site and Infrastructure Subgroup (Divisions 30–39) – Covers civil, site, utility, and infrastructure work, such as earthwork, site utilities, transportation, and similar site/infrastructure elements.

In the modern MasterFormat framework, CSI defines “Facility Services” as the subgroup including divisions for:

Mechanical systems

Electrical systems

Plumbing

Fire suppression / fire protection

Communications and telecom, security, and related low-voltage systems

Therefore, the subgroup that contains MEP (mechanical, electrical, plumbing), fire protection, and telecom systems is:

B. Facility Services Subgroup (Divisions 20–29)

Why the other options are incorrect or incomplete:

A. Site and Infrastructure Subgroup (Divisions 30–39)This subgroup addresses site and infrastructure work, not building internal MEP or telecom systems. Items like site utilities and transportation infrastructure belong here, not typical building MEP systems.

C. Facility Construction Subgroup (Divisions 02–19)This subgroup deals primarily with building fabric and architectural/structural elements (sitework, concrete, masonry, metals, finishes, openings, specialties, etc.). While historically some mechanical/electrical content appeared in lower-number divisions before the 2004 reorganization, in the current CSI structure, MEP and related systems are grouped under Facility Services (20–29), not under Facility Construction.

D. Part 2 – Products“Part 2 – Products” is a component of SectionFormat™, not MasterFormat’s division/group structure. SectionFormat defines the three-part structure of individual specification sections (Part 1 – General, Part 2 – Products, Part 3 – Execution). It doesn’t define which subgroup MEP/telecom systems belong to.

Thus, consistent with CSI’s MasterFormat organization, Option B is the correct answer.