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]: Ammonia is among the ____ most abundantly produced chemicals in the world.\Question: Choose the right answer from options given a) five b) zero c) no d) eight
[EX A]: a

[EX Q]: Reality is more than what can be perceived with the ____ senses.\Question: Choose the right answer from options given a) five b) four c) ten d) one
[EX A]: a

[EX Q]: Mercury fillings are illegal in ____ European countries.\Question: Choose the right answer from options given a) nine b) three c) two d) no
[EX A]:
b