Which part of the 14 CFR provides the information on instrument range markings for transport category airplanes?

The correct choice highlights that Part 25 of the 14 CFR, known as the Federal Aviation Regulations for transport category airplanes, specifically addresses the requirements related to aircraft design and operating standards. This includes detailed provisions for instrument range markings, ensuring that transport category airplanes have clear and functional indicators for various operational parameters.

Part 25 encompasses the safety and performance criteria critical for transport aircraft, focusing on aspects such as airworthiness and operational capabilities. The inclusion of specified instrument range markings is crucial for ensuring pilots can accurately interpret data displayed during flight, contributing to flight safety and operational efficiency.

While other parts, like 23, 27, and 29, pertain to different categories of aircraft – general aviation, rotorcraft, and other types respectively – they do not cover the requirements specific to instrument range markings for transport category airplanes. This distinction underscores the relevance of Part 25 in the context of the question.