Final answer:
Option B, where Ava forgets information about the bones in the hand after studying the bones in the foot, represents retrograde interference.
Step-by-step explanation:
The question asks which of the provided options is an example of retrograde interference, which occurs when newly learned information hinders the recall of older information.
The correct answer is (B) Ava, a medical student, failed her test on the bones in the hand because she studied for the bones in the foot after studying the hand.
This exemplifies retrograde interference because Ava's more recent study of the foot bones is hindering her ability to recall the hand bones she studied earlier, which is characteristic of retroactive interference.