What is the source of this question? It is very poorly worded question with a lot of ambiguities. I would be worried if you are practicing from these resources.
The question does not even tell us which side out of a,b and c is the greatest. For an acute angled triangle if a, b and c are the 3 sides of the triangle and a is the largest side then the triangle is an acute if a^2 < b^2 + c^2. This is the property the question is trying to test but in a very bad way.