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').

Plants can grow from ____ and a half feet tall to over eight feet in height.\Question: Choose the right answer from options given a) five b) one c) nine d) ten

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
b