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').

Evolution is dependent on ____ forces.\Question: Choose the right answer from options given a) no b) five c) two d) seven
c

Stable oxygen has eight protons and ____ neutrons.\Question: Choose the right answer from options given a) eight b) ten c) three d) zero
a

Scullers use ____ oars, sweep oarsmen pull just one.\Question: Choose the right answer from options given a) two b) four c) five d) one

a