Answer: The correct option is (B) 90°.
Step-by-step explanation: We are given to find the measure of ED in circle H.
The measure of ED is equal to the the angle subtended by arc ED at the centre 'H' of the circle.
Given that,
m∠DHG = 90°.
Also, the line segment EG passes through the centre 'H', so EG is the diameter of the circle.
Since the diameter subtends an angle of 180° at the centre, so we have
m∠EHG = 180°.
Therefore, we have
m∠EHD + m∠ DHG = 180°
⇒ m∠EHD = 180° - m∠DHG = 180° - 90° = 90°.
Hence, we must have
ED = 90°.
Thus, (B) is the correct option.