Did you ever hear of "singing sand"? This is the kind of sand that makes bizarre sounds when it is walked on or driven over, or when the wind blows across its surface. The sound such sand makes often has a musical tone (音调). In the United States, singing sand has been found along the seashore in Massachusetts and in the sands north of Alamosa, Colorado. People in different parts of the world have given these musical sands different names. In South Africa they are called "crying sands". In Hawaii they are called "barking sands." And in Afghanistan(阿富汗) they are called "drumming sands." But no matter what the sands may be called, scientists have not yet agreed on what causes them to make such strange sounds.The best title for this passage is ____A. Wind and SandB. Crying SandsC. Musical Sands