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').

Microwave ovens emit ____ kinds of radiation.\Question: Choose the right answer from options given a) six b) two c) four d) eight
b

Mares abort suddenly without signs of illness, and the fetus shows ____ signs of degenerative change.\Question: Choose the right answer from options given a) zero b) no c) seven d) ten
b

Maize streak is harmless if it occurs more than ____ weeks after the maize crop has germinated.\Question: Choose the right answer from options given a) ten b) seven c) eight d) two

c