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').

Q: Angiosperms inhabit all ____ continents, as well as the oceans.\Question: Choose the right answer from options given a) five b) seven c) three d) zero

A: b
****
Q: People can go without food for up to about ____ weeks.\Question: Choose the right answer from options given a) three b) one c) nine d) four

A: a
****
Q: Most dens are oval shape, ____ to nine feet long and about six feet in height and width.\Question: Choose the right answer from options given a) nine b) no c) three d) six

A:
d
****