10)Which one is not mentioned as a sand type in this passage?

READING PASSAGE 1 You should spend about 20 minutes on Questions 1-14, which are based on Reading Passage 1 below. Sand Dunes A One of the main problems posed by sand dunes is their encroachment on human habitats. Sand dunes move by different means, all of them aided by the wind. Sand dunes threaten buildings and crops in Africa, the Middle East, and China. Preventing sand dunes