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').

Pandas reach adulthood at about ____ years of age.\Question: Choose the right answer from options given a) eight b) seven c) five d) six
c

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

Ales actively ferment with yeast for two to ____ days.\Question: Choose the right answer from options given a) five b) nine c) three d) six

c