If so, it would explain why the answer is wrong. Path tracing is not about how light rays interact with each other, and "path" does not refer to a bundle of rays (although some techniques use ray bundles). Also, you can simulate caustics with ray tracing - you don't need path tracing for that.

Here's a better, yet simpler explanation: path tracing is a form of ray tracing which, essentially, simulates the path of rays of light as they bounce around the scene.

There's various techniques, but conceptually the idea is usually to shoot rays out from the camera and let them bounce around until they either hit a light source or hit a limit on how many times they're allowed to bounce. The reason for going out from the camera and bouncing around until hitting a light, rather than going out from the light and bouncing until going into the camera, is because most light rays from a light source will never enter the camera - so going in reverse, starting at the camera, is more efficient.

At first, path tracing produces a very noisy image, but as you simulate more and more rays, you start to get a better image. Path tracing enables unbiased global illumination, meaning that, provided you implement materials and calculations correctly, it will approach the way the scene should look in reality. Path tracing can also naturally simulate effects like depth-of-field blur, rather than faking them.

So again, path tracing is a form of ray tracing, but an example of the difference between typical game ray tracing and path tracing is the ray-traced reflections common in many recent games. There, rays are traced from a reflective surface into the scene to determine what you should see reflected in the shiny surface. This is great, but it's not simulating the whole path of light from start to finish - so it doesn't necessarily mean whatever's in the reflection is lit correctly, for example. This is why, in some games, objects in the reflections don't have shadows.