Find a number in a List and return Outcome, but number is in a long string within the cell

I spent all day getting to this point with personnel logs and am stuck.

Cell B3 has "Davis, Jeffery B XX-13 ABCD 325 ERT/YUT"

A list from C3 down to C10 has options 1,2,3,4,5,324,325,326
A list from D3 down to D10 has options a,b,c,d,e,f,g,h

I'm trying to get cell A3 to be populated with the letter G since "325" is in cell B3, 325 is in cell C9, and the letter G is in cell D9.