I have two spreadsheets. One is called Item numbers and one is called Master List

Item Numbers: Col A has the item number and Col B has the vendor number Col C has a Vendor Category
Master List: Col C Has the Item Number and Col Q has the vendor number

Basically I need to have a formula to say, if what is in A & B on the Item Numbers sheet is the same as what is in C & Q on the Master List, then give me what is in Col C on the Item Number sheet.

Hope that makes sense.
I am not sure if this is an index and match function? I get confused when there are multiple columns and sheets to compare.