In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: Many comets have _ tails.
[EX A]: two

[EX Q]: Mental illness affects _ out of four families in America.
[EX A]: one

[EX Q]: Mothers usually give birth to one, two, or _ babies at a time.
[EX A]:
three