Idiom: it's your turn

Test No. [color=blue]incompl/elem-19 “Late Again”, question 9

Now, it’s your to tell me.

(a) bend
(b) turn
© corner
(d) curve

Test No. [color=blue]incompl/elem-19 “Late Again”, answer 9

Now, it’s your turn to tell me.

Correct answer: (b) turn

The above sentence’s an idiom. Could you pls explain it to me? Thanks. Nice day!

This means that you are next to do something.