In this sentence, the term “human-designed” suggests that mules are
A an animal that enjoys popularity as a pet.
B an animal that can only be bred by people.
C a type of horse unpopular with most people.
D a type of donkey that is easier to train.
The correct answer is B: an animal that can only be bred by people.
Explanation: The term “human-designed” implies that mules are a result of human intervention in breeding, which means they cannot reproduce naturally and are created through deliberate breeding by people. This distinguishes them from animals that breed naturally without human involvement.