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: Ants have ____ stomachs.\Question: Choose the right answer from options given a) two b) nine c) four d) seven
Example Output: a

Example Input: Most ovarian cysts go away on their own in ____ to three months without causing any problems.\Question: Choose the right answer from options given a) one b) ten c) five d) eight
Example Output: a

Example Input: Intussusception occurs most commonly in babies between five and ____ months of age.\Question: Choose the right answer from options given a) nine b) five c) two d) zero
Example Output:
a