Answer
Choice C.
Work Step by Step
Equation 11–11a tells us that the period of a pendulum is proportional to the square root of its length and inversely proportional to the square root of g, $T=2 \pi \sqrt{\frac{L}{g}}$.
The mass of the children (i.e., the mass of the bob) does not affect the period of the pendulum. Both children swing with the same period.
