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: Human females have ____ X chromosomes.\Question: Choose the right answer from options given a) two b) six c) one d) eight

A: a
****
Q: Dogs are pack animals, and ____ dogs is the minimum number for proper socialization.\Question: Choose the right answer from options given a) four b) five c) no d) zero

A: b
****
Q: Dispassion is a ____ edged sword.\Question: Choose the right answer from options given a) six b) two c) zero d) four

A:
b
****