How to check .net framework version installed programatically?

Question

Hi, i want to check the .net framework version of the target system, if it doesn't meet 3.X then i wil l start the re-distributable .net framework package. Please don't suggest .net codes to check it. Because to execute the .net application, i am going to check the framework. Then the code to check is in .net means, how it works. So, I need the code in c language or in terms of Batch file. Please Help me! Thanks in advance