Answer:
The measure of arc DEF is 204°
B is correct
Explanation:
In a circle center at O.
∠DOF and ∠DEF are lie on same base but ∠DOF at center and ∠DEF on circle.
Thus, ∠DOF = 2 ∠DEF
minor ∠DOF = 2 x 78 = 156°
We need to find arc DEF.
DEF is central angle of major∠DOF
major∠DOF + minor ∠DOF = 360° (Complete angle at center)
major∠DOF + 156° = 360°
major∠DOF = 204°
major∠DOF is arc DEF.
Hence, The measure of arc DEF is 204°