Answer:
B. was a naturalist who was inspired by his observations of variation in the natural world
Step-by-step explanation:
Charles Darwin is well-known for his theory of evolution through natural selection, and he developed this theory based on his observations of variation in the natural world during his travels and studies. Option B accurately describes his contributions to science. The other options are not correct: Mary Anning was not a co-author of "On the Origin of Species," Darwin did not write his theory while still on board the Beagle but developed it over time, and he did not immediately publish his theories upon his return.