【单选题】

Questions 17～20 are based on the following report about human height. You now have 20 seconds to read Questions 17～20. The author would most probably agree ______.

A、non-Americans add to the average height of the nation
B、human height is conditioned by the upright posture
C、Americans are the tallest on average in the world
D、larger babies tend to become taller in adulthood