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

Urea cycle requires the coordination of ____ different tissues.\Question: Choose the right answer from options given a) two b) four c) nine d) zero
a

Masturbation tends to peak when children are between the ages of ____ and five.\Question: Choose the right answer from options given a) three b) eight c) seven d) ten

a