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').

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

[EX Q]: Chemistry has ____ less important names.\Question: Choose the right answer from options given a) ten b) no c) eight d) nine
[EX A]: b

[EX Q]: Bears have ____ digits on each dextrous paw, each digit with a long non-retractable claw.\Question: Choose the right answer from options given a) five b) seven c) one d) three
[EX A]:
a