Identify the parts of the body that would be used to support oneself as a gymnast when performing a headstand.

30. Identify the parts of the body that Ruto would use to support himself as a gymnast when performing a headstand.
In a headstand, a gymnast typically forms a stable base with three points of contact on the ground: the top of the head and both hands. This creates a tripod-like support structure, allowing the body to balance upside down.

The final answer is $\boxed{\text{C. Hands and top of the head.}}$.