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').

Input: Consider Input: Avian kidneys have ____ kinds of nephrons.\Question: Choose the right answer from options given a) four b) eight c) no d) two

Output: d


Input: Consider Input: Women live an average of five to ____ years longer then men.\Question: Choose the right answer from options given a) one b) five c) ten d) seven

Output: d


Input: Consider Input: Heavy chain has one V region and ____ or more C-regions.\Question: Choose the right answer from options given a) two b) zero c) five d) three


Output: d