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: Insects have ____ common types of metamorphosis.\Question: Choose the right answer from options given a) six b) eight c) two d) seven
Example Output: c

Example Input: Gasoline is ____ times as expensive as in the United States.\Question: Choose the right answer from options given a) two b) four c) three d) ten
Example Output: c

Example Input: Children are most vulnerable to the sun during their first ____ years.\Question: Choose the right answer from options given a) ten b) zero c) four d) eight
Example Output:
a