Step-by-step explanation:
The sentence that contains a metaphor is: "Are they brown and ugly like a potato?"
The sentence "Are they brown and ugly like a potato?" contains a metaphor because it compares the appearance of something (presumably rocks or stones) to that of a potato, using the word "like". The metaphor creates a mental image in the reader's mind by comparing two unlike things in order to help the reader understand or visualize the appearance of the rocks or stones. In this case, the metaphor suggests that the rocks or stones are brown and unattractive, much like a potato.