When the central angle is in radians, the arc length formula is simpler than with degrees. Think about the formula involving radius times angle in radians.

A full circle is $2\pi$ radians. How does $\dfrac{2\pi}{3}$ compare to $2\pi$? Use that fraction of the full circumference to find the arc length.

In Desmos, type 60pi/(2pi) to compute the radius using $r = \dfrac{C}{2\pi}$. Note the numerical value of the radius from the output.

In a new expression line, multiply the radius you found by the angle in radians: type (<radius>)*(2pi/3), replacing <radius> with the value from step 1. The output is the length of arc $XY$ in meters; match this value to the closest answer choice.

Use the circumference formula $C = 2\pi r$ and the given circumference $60\pi$ to find the radius.

So the radius of the circle is $30$ meters.

For a central angle measured in radians, arc length $s$ is given by $s = r\theta$, where $r$ is the radius and $\theta$ is the central angle in radians.

Here, $r = 30$ and $\theta = \dfrac{2\pi}{3}$, so

Simplify the expression for $s$:

So the length of arc $XY$ is $20\pi$ meters, which corresponds to choice B.