This part is the Airworthiness Standards: Transport Category Aircraft:

The correct choice indicates the section of the Code of Federal Regulations that establishes the airworthiness standards specifically for transport category aircraft. 14 CFR Part 25 outlines the specific design and performance requirements that aircraft must meet to be considered safe for operation in the transport category. This includes larger aircraft typically used for commercial airline service, which must comply with rigorous standards for structural integrity, safety systems, and performance capabilities.

Transport category aircraft are subject to stricter regulations due to the higher number of passengers and the greater potential for risk associated with their operation. The standards in Part 25 ensure that these aircraft meet stringent safety, reliability, and operational performance criteria.

The other options relate to different categories and types of aircraft. For example, 14 CFR Part 23 provides airworthiness standards for smaller general aviation aircraft, while 14 CFR Part 125 applies to commuter category aircraft, which are typically smaller than those in the transport category. As such, these other parts do not encompass the broader and more rigorous requirements that are essential for transport category aircraft safety.