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').

Electrolytic capacitors have a finite lifetime, usually about ____ years.\Question: Choose the right answer from options given a) zero b) ten c) four d) eight
b

Chemical interactions are essentially electron interactions of ____ atoms.\Question: Choose the right answer from options given a) six b) no c) ten d) two
d

Coaxial relays allow the selection of up to ____ antennas per cable.\Question: Choose the right answer from options given a) nine b) three c) six d) one

b