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').

Nodes are points in space that have ____ probability for locating an electron there.\Question: Choose the right answer from options given a) no b) six c) zero d) three
c

Couples often date from one to ____ years before getting engaged.\Question: Choose the right answer from options given a) three b) nine c) eight d) seven
a

Professional wrestlers work day and night, ____ days a week, entertaining millions of people.\Question: Choose the right answer from options given a) six b) seven c) three d) four

b