Change content of a cell based on a value in a different cell

Hello,

I would like to be able to total values based on an index number and put the total in a different cell.

Here is an example:
If cell C2 has 2 in it I would like to take value from D2 and add it to I2
If cell C3 has 4 in it I would like to take value from D3 and add it to K2
If cell C4 has 2 in it I would like to take value from D4 and add it to I2

C D I2 J2 K2
2 2 5 5 0 0
3 4 8 5 0 8
4 2 10 15 0 8
5
6