Explanation:

Correct option:3(30^o)

A chord of a circle, which is equal to the radius of the circle. Radius of the circle = 9 cm

Concept Used: 
In a circle, the angle subtended by an arc at the center is twice the angle subtended by it at the remaining part of the circle. 
The length of chord = radius = 9cm
It forms an equilateral triangle with each angle at 60°
The angle subtended by the chord at the center = 60°
By using the theorem, the angle subtended in the major segment is half of the angle subtended at the center. 60°/2 = 30°
Therefore, the angle subtended by the chord in the major segment is 30°.