In a circus where performers share dressing rooms, training spaces and work in a fast-paced environment, the success of a show __________ fostering team-work and
collaboration.

The sentence describes how a circus show's success depends critically on teamwork and collaboration, given the shared spaces and fast-paced work environment. The blank requires a phrasal verb meaning "depends essentially on" or "is determined by."

"Comes down to" (Option A) is the perfect fit because it literally means "boils down to" or "depends fundamentally on." 

"Comes about" (option B) means to happen or occur, "Come along with" (option C) means to accompany someone, and  "Comes with" means to include as a feature; none of which are relevant to the requirement here. 

The correct answer is therefore Option A.