Concept:The time period of a simple pendulum depends on the acceleration due to gravity, which decreases as we move to a height above the earth's surface.Explanation:The time period of a simple pendulum on the earth's surface is given by:T=2πgl​​Here, l is the length of the pendulum and g is the acceleration due to gravity on the surface.We know that g=R2GM​, where G is the gravitational constant, M is the mass of the earth, and R is the earth's radius.When the pendulum is taken to a height R above the surface, its distance from the centre of the earth becomes R+R=2R.The new acceleration due to gravity at this height is:g′=(2R)2GM​=4R2GM​=4g​The new time period is therefore:T′=2πg′l​​=2πg/4l​​=2πg4l​​T′=2×2πgl​​=2TGiven that the new time period is xT, we equate:xT=2Tx=2Answer:The value of x is 2, which is option C.