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

[EX Q]: Parliaments can last five years, often last ____ and a bit.\Question: Choose the right answer from options given a) four b) three c) five d) two
[EX A]: a

[EX Q]: Toucans live in small flocks of five or ____ birds.\Question: Choose the right answer from options given a) four b) zero c) eight d) six
[EX A]:
d