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: Heme is made of ____ pyrrole groups united to form a porphyrin ring.\Question: Choose the right answer from options given a) five b) four c) eight d) six

Output: b


Input: Consider Input: Cleavage is good in ____ directions forming cubes.\Question: Choose the right answer from options given a) two b) three c) six d) zero

Output: b


Input: Consider Input: Genesis is the first of ____ books of the Torah called the Pentateuch.\Question: Choose the right answer from options given a) eight b) five c) no d) three


Output: b