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').

Ex Input:
Water softeners add sodium to drinking water in ____ ways.\Question: Choose the right answer from options given a) zero b) six c) two d) nine

Ex Output:
c


Ex Input:
Sugar beet is strongly self-sterile setting few or ____ seeds under strict isolation.\Question: Choose the right answer from options given a) three b) no c) five d) nine

Ex Output:
b


Ex Input:
Frogs commonly have four legs and ____ foot on each leg.\Question: Choose the right answer from options given a) three b) nine c) one d) five

Ex Output:

c