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: Brain death occurs in just four to ____ minutes unless the heart rhythm is restored.\Question: Choose the right answer from options given a) ten b) three c) six d) nine
Example Output: c

Example Input: Tropical trees can be rampant growers, and can outgrow a wiring in as little as ____ days' time.\Question: Choose the right answer from options given a) four b) eight c) six d) ten
Example Output: d

Example Input: Insects have three pairs of legs and ____ body segments.\Question: Choose the right answer from options given a) four b) two c) no d) three
Example Output:
d