Answer:
------------------
The measure of the inscribed angle is half the measure of its intercepted arc.
In our case the inscribed angle is ∠CDE. The intercepted arc is CBE, the sum of arcs BC and BE. It gives us:
- m∠CDE = (mBC + mBE)/2
- m∠CDE = (64° + 90°)/2
- m∠CDE = 77°
The matching choice is D.