Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').

Example Input: Parapsychologists have ____ basic approaches to their subject matter.\Question: Choose the right answer from options given a) three b) two c) ten d) five
Example Output: b

Example Input: Most children experience at least one episode by the time they are ____ years old.\Question: Choose the right answer from options given a) eight b) one c) ten d) seven
Example Output: d

Example Input: Maggots are legless, white insects that feed from the egg-laying site for ____ to five days.\Question: Choose the right answer from options given a) eight b) four c) zero d) three
Example Output:
d