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: Vaccination typically occurs at ____ to eight weeks of age in kittens.\Question: Choose the right answer from options given a) three b) nine c) six d) no
Example Output: c

Example Input: Photosynthesis occurs in ____ phases.\Question: Choose the right answer from options given a) four b) two c) nine d) five
Example Output: b

Example Input: Exports account for one out of ____ manufacturing jobs in the United States.\Question: Choose the right answer from options given a) eight b) five c) two d) three
Example Output:
b