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: Summer is the hottest of the ____ temperate seasons , falling between spring and autumn .\Question: Choose the right answer from options given a) six b) four c) no d) nine
Example Output: b

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

Example Input: Protein has ____ calories of energy per gram.\Question: Choose the right answer from options given a) four b) no c) zero d) eight
Example Output:
a