Taking simple averages with variable ranges using multiple criteria

Hey everyone,

I have a file with a list of counties in column A, a list of their respective states in column B and a corresponding value in column C. I am trying to take the averages of the values in column C based upon state and county.

The problem I am running into is that there are a different number of counties per state and the county names are often repeated. Ideally, the end result would be a formula that gives me county X in state Y with average Z that can be dropped down 10,000+ rows.

My attempt at this based upon previous feedback on this forum from a related question is the following equation:
=SUMIF($A$2:$C$7856, A2,$C$2:$C$7856)/COUNTIF($A$2:$C$7856,A2)


However, this does not filter by state as well so if the name Harrison repeats in both Alabama and Ohio, the equation averages both of the counties.
Attached is a sample workbook.

Much appreciated.