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').
--------
Question: Some olive trees live to be ____ thousand years old.\Question: Choose the right answer from options given a) ten b) zero c) two d) seven

Answer: c


Question: Corms are undifferentiated, uniform, and contain ____ rings when cut apart.\Question: Choose the right answer from options given a) no b) three c) one d) zero

Answer: a


Question: Buses are ____ times as fuel efficient as cars.\Question: Choose the right answer from options given a) five b) one c) four d) eight

Answer:
a