Since congruent triangles are the exact same figures, then triangle ABC is the exact same shape as triangle DFE. Hence, as I don't have any additional information to find x, x would be the same for both figures.
If something is perpendicular to something else, it intersects it at 90 degrees. So, it there is a bisector perpendicularly bisecting a segment, it means they are crossing at a 90 degree angle. Your answer should be B.
