Question

If triangle DEF has a 90° angle at vertex E, which statements are true? Check all that apply.

Answer 1

I will say it b  is right

Answer 2

Listed below are those that are true:

The angle at vertex D is acute.
Triangle DEF is a right triangle.

We know D is acute, because a triangle has 180 internal degrees, and E is 90 degrees, so D has to be less than 90 which makes it acute.
Also, since E is 90 degrees, the triangle is a right triangle.