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: Double price is based on two golfers sharing ____ room.\Question: Choose the right answer from options given a) one b) zero c) six d) nine
Example Output: a

Example Input: Trains kill ____ people every year.\Question: Choose the right answer from options given a) zero b) three c) no d) four
Example Output: d

Example Input: Birds have ____ eyes.\Question: Choose the right answer from options given a) eight b) five c) nine d) two
Example Output:
d