There is an office building with a regularly occupied project area of 25.

Here's the relevant detail from the WELL Building Standard:

T05: Radiant Thermal Comfort requires at least 50% of the floor area in regularly occupied spaces to be serviced by radiant heating and/or cooling systems.

Since the office building has a regularly occupied project area of 25,000 ft², to meet T05, a minimum of 50% x 25,000 ft² = 12,500 ft² must be serviced by radiant heating or cooling.

However, the image clarifies that Option C (10,000 ft²) meets the minimum requirement, not Option D (12,500 ft²). It's possible there might be additional considerations beyond the WELL standard that influence this specific scenario.