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: Interpersonal conflict exists whenever ____ or more people disagree.\Question: Choose the right answer from options given a) five b) seven c) no d) two
Example Output: d

Example Input: Respiratory therapists complete ____ to four years of education.\Question: Choose the right answer from options given a) one b) nine c) zero d) two
Example Output: d

Example Input: State law requires all dogs and cats ____ months of age or older to be vaccinated against rabies.\Question: Choose the right answer from options given a) three b) zero c) nine d) five
Example Output:
a