In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: White sturgeon inhabit _ large river systems, all on the western coast of North America.
[EX A]: three

[EX Q]: Some people have _ or four careers during their lives.
[EX A]: three

[EX Q]: Carbon has _ protons and six electrons.
[EX A]:
six