The following question, consist of two words each that have a certain relationship to each other, followed by four lettered pairs of words. Select the lettered pair that has the same relationship as the original pair of words: Botany : Plants :: Entomology : ?

Answer: Option B

Botany is the branch of science which deals with the study of plants. Similarly, Entomology is the branch of science which deals with the study of insects.
Hence, the answer is (b).