Which is the correct chronological order of the following rulers of slave dynasty who ruled over Delhi ?
1. Iltutmish, Balban, Nasiruddin, Razia
2. Razia, Nasiruddin, Balban, Iltutmish
3. Nasiruddin, Balban, Razia, IItutmish
4. Iltutmish, Razia, Nasiruddin, Balban