Correct Answer:
B. Fossils: Paleontologist
The correct answer is Fossils: Paleontologist. This is an analogy based on the relationship between a specialist and the object of their study. A geologist studies shale (a type of rock). Similarly, a paleontologist studies fossils. 'Reef: Astrologist' is incorrect because an astrologist studies stars, not reefs. 'Biologist: Plants' has the order reversed. 'Catacombs: Entomologist' is incorrect because an entomologist studies insects, not catacombs. Therefore, 'Fossils: Paleontologist' is the correct analogy.