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').

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
a

Shamrocks can be ____ of four leafs.\Question: Choose the right answer from options given a) six b) seven c) zero d) three
d

Sediment consists of ____ visually distinct floc layers.\Question: Choose the right answer from options given a) two b) five c) zero d) six

a