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: Chlorine has ____ naturally occurring isotopes.\Question: Choose the right answer from options given a) nine b) eight c) three d) two

Output: d


Input: Consider Input: Sexual maturity occurs at three to four years for females and ____ to five years for males.\Question: Choose the right answer from options given a) nine b) seven c) five d) four

Output: d


Input: Consider Input: Hydra has ____ cell lineages, which are all self-renewing and maintained by stem cells.\Question: Choose the right answer from options given a) nine b) one c) five d) three


Output: d