Exercising like a zombie

People do all kinds of exercises in the morning. Taichi, sword dancing, whipping and square dancing seem all absolutely normal these days. But there's one activity that looks a bit odd. About 40 people use their hands and feet to crawl in the park in the morning. According to one of the participants, walking on all fours helps her fix cervical vertebra problems. A doctor of traditional Chinese medicine said crawling will take the pressure off the lumbar vertebra and coordinate all the body parts.

How many people crawl in the park to do their morning exercises?

A. About 40

B. About 50

C. About 60