Answer:
C
Step-by-step explanation:
Since XY = XZ = 6, then the triangle is isosceles.
The base angles are therefore congruent, that is
∠ Y = ∠ Z = 70°
The sum of the 3 angles in the triangle = 180°, thus
∠ X = 180° - (70 + 70)° = 180° - 140° = 40° → C
