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: Aridity presents ____ main obstacles to solitary behavior.\Question: Choose the right answer from options given a) no b) three c) two d) five

Output: c


Input: Consider Input: Carbon forms ____ bonds.\Question: Choose the right answer from options given a) five b) four c) two d) three

Output: b


Input: Consider Input: Adult tarantulas require a minimum of three to ____ crickets a week.\Question: Choose the right answer from options given a) eight b) seven c) three d) five


Output: d