Answer:
C, D and F are true
Step-by-step explanation:
The DCB triangle is isosceles, so it means the angles D and B are the same and as the angle C is 90°, B and C need to be 45° (because the sum of the internal angles of a triangle is always 180°). The sin(B) = sin(C) = sqrt2/2 and the tan(B) = tan(C) = 1
