What is "tax free employer tuition assistance" and what qualifies for it?

I don't understand "tax free employer provided assistance" question as I'm completing the information for my 1098t. 

What is tax free employer provided assistance?

I received a Pell Grant, Tuition Aid Grant, Federal Loans (direct, unsub, and parent), and New Presidential Scholar. With this I still had to pay some money to go to school. 

The question asks what portion was tax free employer provided assistance for Box B of my 1098t and I don't know what is the correct answer.