What is the approximate altitude of the troposphere?

The troposphere is the lowest layer of the Earth's atmosphere and extends from the Earth's surface up to an altitude that typically ranges between about 7 to 12 miles, or approximately 36,000 feet, depending on geographical location and weather conditions.

At the equator, the troposphere can reach higher altitudes due to the warmer temperatures, while at the poles it is generally lower due to cooler conditions. This layer is crucial for weather phenomena and is where most of the atmosphere's mass resides, containing approximately 75% of the atmosphere's overall mass and the majority of its water vapor.

Thus, the correct answer reflects the general upper limit of the troposphere, making it up to 36,000 feet. The other choices represent altitudes that are either too low or too high regarding the typical boundary of the troposphere.