This figure shows the angular displacement of a pendulum on a planet with twice the earth's gravity. How long is the pendulum's string? A graph titled Angular Displacement of Pendulum. The horizontal axis is labeled Time, in seconds, and extends from 0 to 5.0 with an interval of 1.0. The vertical axis is labeled Angular Displacement, in radians, and extends from negative 0.3 to positive 0.3 with an interval of 0.1. The graph shown is a sine wave beginning at the origin. The sine wave peaks are at about 2.5 and its troughs are at about negative 2.5. From 0 to 5 seconds, the sine wave completes about 5 and one-half cycles.

A) 3.22 m

B) 0.80 m

C) 0.40 m

D) 1.61 m