Count Unique Values IF a Column Contains Data

So I've been looking through many posts on this forum as well as other sites like exceljet and mrexcel, but I could not find an answer to my below issue. If I've overlooked a thread that you think would be helpful, then please let me know!

I have a set of columns with data in the rows below the columns. I am attempting to count the unique values in column A by the three various care levels that are in column D. I've tried a few different formulas including countif, sumif, sumproduct with a 1/countif, frequency, etc but I just can't put one together to get me the info.

I am using Office 2007 and in the below data, I would basically want to know how many units are AL, IL, and DM. It should be 2 AL, 3 IL, 3 DM. So I would want a formula that does IF column D contains AL count how many unique values are in column A.

Unit	Type		Privacy	Care Level
1	alstudio   	PRI	AL
2	al2br		SPA	AL
2	al2br		SPB	AL
3	al1br		PRI	DM
4	al1br		SPA	DM
4	al1br		SPB	DM
5	al2br		SPA	IL
5	al2br		SPB	IL
6	alstudio   	PRI	DM
7	al2br		PRI	IL
9	al1br		PRI	IL

Any help is greatly appreciated, and if there's additional info that I didn't provide please let me know! Thanks!