Which of the following is true of high clouds?
a. they eventually evaporate to form fog.
b. they do not usually bring precipitation.
c. they are composed mostly of liquid water.
d. they generally produce hail and tornadoes.

Option B

Explanation:

Clouds which are founds at greater heights from the surface of earth are known as High clouds. These clouds usually occur at heights ranging from 6000 meters or 20,000 feet. At such height, these clouds consists of thin layer of ice crystals thereby allowing sunlight and hence signal a clear, fair weather. For example Cirrocumulus and cirrostratus clouds are high level clouds. Therefore, these clouds are not associated with rainfall or any form of precipitation.

hence, option B is correct

the answer is definitely a