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: Urea cycle requires the coordination of ____ different tissues.\Question: Choose the right answer from options given a) two b) four c) nine d) zero

Output: a


Input: Consider Input: Children now account for only ____ percent of all forest fires caused in the United States.\Question: Choose the right answer from options given a) five b) four c) eight d) nine

Output: b


Input: Consider Input: Bushes are woody like trees, but have multiple stems and are generally less than ____ meters tall.\Question: Choose the right answer from options given a) seven b) ten c) three d) zero


Output: b