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').

Q: 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: a
****
Q: Motor neurons are divided into ____ groups.\Question: Choose the right answer from options given a) two b) six c) seven d) eight

A: a
****
Q: Some ecosystems have ____ or more levels of consumers.\Question: Choose the right answer from options given a) four b) no c) three d) nine

A:
a
****