The correct order of size of the given species is: 

1. I > I– > I+ 2. I> I– > I
3. I > I> I 4. I– > I > I+

HINT: Size of anion is greater than size of cation of same element.

Explanation:

Anion formed after the gain of electron to the neutral atom and cation formed after the loss of electron from outer shell.

Hence, cation has smaller size but anion has bigger size than its neutral atom.

Thus, the order is I> I > I+