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:
All cattle have a ____ chambered stomach, consisting of a rumen, reticulum, omasum and abomasum.\Question: Choose the right answer from options given a) ten b) four c) six d) two

Ex Output:
b


Ex Input:
Natural chlorine contains ____ isotopes.\Question: Choose the right answer from options given a) two b) six c) eight d) seven

Ex Output:
a


Ex Input:
Many ticks can live as long as ____ to five months between each stage.\Question: Choose the right answer from options given a) two b) seven c) three d) eight

Ex Output:

c