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').

TriMetal Irons Discover the benefits of ____ different metals.\Question: Choose the right answer from options given a) five b) seven c) no d) three
d

Sexual reproduction is varied in ____ ways.\Question: Choose the right answer from options given a) seven b) two c) five d) three
d

Mares can have one or ____ foals.\Question: Choose the right answer from options given a) four b) one c) two d) zero

c