Which of the following are state functions?
(a) Height of a hill
(b) Distance travelled in climbing the hill
(c ) Energy change in climbing the hill

Explanation

To determine which of the given options are state functions, we need to understand the definitions of state functions and path functions.

### Definitions:
1. **State Function**: A property whose value depends only on the state of the system, not on how it got there. Examples include height, pressure, temperature, and energy.
2. **Path Function**: A property that depends on the specific path taken to reach a particular state. Examples include distance traveled and work done.

### Given Options:
(a) Height of a hill
...