Which process(es) is/are involved in the turning of starch iodide paper blue-black by chlorine gas?

A.

chlorine attacks the starch to give the blue-black color

B.

chlorine attacks the iodide ion to give the blue-black color

C.

chlorine oxidizes the iodide ion to produce iodine which attacks the starch to give the blue-black color

D.

iodine attacks the starch to give the blue-black color

Correct answer is C

No explanation has been provided for this answer.