Confusing!

I'm really confused with this. If any one can help me I would be so grateful guys. I've come across this fill in the gap Q:
*I'm going to the bank .......... a check
the two options I'm confused about are: A- to deposit B- for depositing
I choose "for depositing" though I don't know whether I'm right or wrong and why I'm right or wrong any way thanks in advance.