Identify and label string occurrences in data

[jmarcuzb]

Hello all. I am a long time reader and first time poster. I have a peculiar problem that I need help with.

I have a set of data containing 3 columns (dummy data here). The issue is that this data looks like duplicates 

so I need a way to identify and incrementally label each occurrence of this data. This is important further in the process.

Columns A, B and C are what I have. Column D is what I want to add to this data. I have attached this dummy data.

Thanks

Jon

[jmarcuzb]

@MarqueeCrew, @binuacs  Sorry guys, I got tied up for a little while. Yes you are correct, I marked it as a solution also. Thanks again everyone! Also thanks to @DataNath although I didn't get to use your solution for this issue.