Comparing 2 column for matches
 

I am wanting to compare 2 columns for exact matching. If there are two
matching items I want to be able to say "A match" in a chosen cell for all
the ones that match. Column C will be retrived in an random order... so how
would I write the formula for that?????

Example:
A B C
45time 11tune
A match 11tune 89time
47doog 43jkjkj
A match 123ABC 123ABC

If possible include how to highlight the ones that make as another option.
Thanks