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

[EX Q]: Monarch caterpillars have _ pairs of tentacles.
[EX A]: two

[EX Q]: Asian lions divide themselves into _ prides.
[EX A]: two

[EX Q]: Most jet airplanes have two, _ or four engines, depending on aircraft size.
[EX A]:
three