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').

Quarks also come in ____ 'colours', terms for a property a little like electrical charge.\Question: Choose the right answer from options given a) three b) nine c) six d) no
a

Spores have ____ combinations of sexes.\Question: Choose the right answer from options given a) four b) five c) seven d) three
a

Tobacco now kills ____ million people each year world-wide.\Question: Choose the right answer from options given a) seven b) three c) zero d) one

b