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').

Natural tellurium consists of ____ isotopes.\Question: Choose the right answer from options given a) six b) seven c) eight d) one
c

Many animals use two or ____ forest structure types.\Question: Choose the right answer from options given a) eight b) zero c) two d) three
d

Parallel ports use eight wires to send eight bits in parallel at ____ time.\Question: Choose the right answer from options given a) five b) one c) zero d) no

b