Which of the following best illustrates a binary operation?

A binary operation involves two inputs and produces a single output based on those inputs. In the context of the options presented, turning on a light can be viewed as an operation that requires two states: off (0) and on (1). It takes the state of the light and an action (the act of turning it on) to yield the result. This fits the definition of a binary operation because it combines an action with a binary state, producing a specific outcome.

On the other hand, adjusting the volume typically involves a continuous input (like a slider or knob) that can take on many values rather than just two distinct states. Changing the channel, while involving a selection between options, does not inherently rely on combining two distinct inputs in the same sense. Calculating speed could be considered a mathematical operation using multiple inputs (such as distance and time), but it does not fit the binary operation definition as cleanly as turning a light on or off does, which is a direct action with a clear binary outcome.