Question

question tag for this Army has an important role to play​

Answer 1

Answer:

Army has an important role to play, hasn't it?

maybe it is correct answer.

Answer 2

Add appropriate question tag:

Question : Army has an important role to play.

Answer : Army has an important role to play. Hasn't it?

The given sentence is positive, so we use a negative question tag with the same helping verb, i.e. has.