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').

Casinos have no windows and they have ____ clocks.\Question: Choose the right answer from options given a) six b) four c) eight d) no
d

Organisms have ____ forms of nucleic acid.\Question: Choose the right answer from options given a) four b) three c) two d) one
c

Heavy chain has ____ V region and three or more C-regions.\Question: Choose the right answer from options given a) six b) one c) ten d) no

b