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: Youth unemployment is ____ times the adult level.\Question: Choose the right answer from options given a) one b) three c) seven d) no
Example Output: b

Example Input: Streptomyces are of special interest for ____ reasons.\Question: Choose the right answer from options given a) nine b) seven c) four d) two
Example Output: d

Example Input: Female sturgeon spawn only every four to ____ years.\Question: Choose the right answer from options given a) one b) three c) seven d) four
Example Output:
c