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: Giraffes sleep less than ____ hours a day.\Question: Choose the right answer from options given a) two b) six c) seven d) ten

Output: a


Input: Consider Input: Alleles fall into ____ classes based on somatic, gonadal and dauer phenotypes.\Question: Choose the right answer from options given a) ten b) six c) eight d) no

Output: b


Input: Consider Input: Ozone adds ____ contaminants or by-products to water.\Question: Choose the right answer from options given a) nine b) no c) ten d) three


Output: b