Final answer:
The stratosphere commences at approximately 10 kilometers (about 32,808 feet) above the Earth's surface, which is the upper boundary of the troposphere. The correct answer is B. 36,000 ft.
Step-by-step explanation:
The stratosphere commences at an altitude approximately above the Earth’s surface. This is where the troposphere ends and the stratosphere begins. The troposphere extends up to about 6 miles or 10 kilometers (km) in altitude, which is where human activities are predominantly located, including the peak of Mt. Everest at about 5.6 miles (9 km) high. The stratosphere continues from about 10 km to 50 kilometers above the Earth's surface. The majority of commercial airplanes fly in the lower part of the stratosphere. Considering the options provided, the correct answer would be B. 36,000 ft, which is approximately 11 kilometers, and it's within the lower part of the stratosphere.