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 spiders have ____ eyes, some only six and several have fewer or none.\Question: Choose the right answer from options given a) ten b) two c) eight d) no
Example Output: c

Example Input: Coffee trees reach maturity between ____ and four years when their clusters of fruit turn deep red.\Question: Choose the right answer from options given a) no b) three c) nine d) five
Example Output: b

Example Input: Sphericity is calculated using ____ different formulas.\Question: Choose the right answer from options given a) four b) seven c) three d) six
Example Output:
c