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: Altimetric satellites are usually limited life missions lasting approximately three to ____ years.\Question: Choose the right answer from options given a) five b) ten c) four d) eight

Output: b


Input: Consider Input: Digital bandwidth enables signal to be condensed as a five to ____ ratio.\Question: Choose the right answer from options given a) one b) nine c) seven d) six

Output: a


Input: Consider Input: Lampreys go through ____ years of larval development before becoming adults.\Question: Choose the right answer from options given a) four b) seven c) ten d) nine


Output: a