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').

Mothers usually give birth to one, two, or ____ babies at a time.\Question: Choose the right answer from options given a) three b) zero c) five d) ten
a

Fruit trees are usually safe after ____ years.\Question: Choose the right answer from options given a) five b) four c) no d) three
d

Some comets have short periods of less than ____ years.\Question: Choose the right answer from options given a) one b) four c) zero d) seven

d