DATA Validation and IF statement

Hi,

Here is my challenge.

I have a dropdown menu in column "A" with three selections. In column "B" the user will add a number. Over to the right of the culumns A and B is a table with the three columns of data that corresponds to the three selections from column "A" as well as numbers that will correspond to the number added under column "B". Drop down options are the headings, inputs from "B" fill the rows. The user will input his number in column "B" and based on that, that number will correspond to a number under the three selections in the table and appear in culumn "C".

So, the user will choose a selection from the drop down "A", input his number in "B", and column "C" should populate itself based on the criteria observed from the table to the right.

Thanks so much!