Final answer:
In the International Standard Atmosphere, the height of the tropopause, the upper boundary of the troposphere, is approximately 11,000 meters.
Step-by-step explanation:
In the International Standard Atmosphere (ISA), the height of the tropopause, which marks the upper boundary of the troposphere, varies by latitude but is approximately 11,000 meters (36,089 feet) above mean sea level at mid-latitudes. It is higher in the tropics, up to about 17,000 meters (55,774 feet), and lower at the poles, around 9,000 meters (29,528 feet). The correct answer to the student's question is B. 11,000 meters.