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: Most females are sexually mature at about ____ to six years.\Question: Choose the right answer from options given a) eight b) nine c) five d) two
Example Output: c

Example Input: Mechanical digestion occurs as ____ strong layers of muscle contract to produce a churning motion.\Question: Choose the right answer from options given a) four b) no c) three d) six
Example Output: c

Example Input: Whiteflies cause ____ types of damage to plants.\Question: Choose the right answer from options given a) zero b) five c) four d) two
Example Output:
d