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').

Q: Conglomerate integration is when ____ apparently unconnected companies merge.\Question: Choose the right answer from options given a) two b) six c) no d) three

A: a
****
Q: Diatoms look like ____ shells that fit together.\Question: Choose the right answer from options given a) zero b) one c) two d) seven

A: c
****
Q: Marriage is union of ____ families.\Question: Choose the right answer from options given a) three b) two c) four d) zero

A:
b
****