What does a kilobyte indicate?

A kilobyte $(KB)$ is a unit of measure. It equals about $1$ million bytes.

A kilobyte $(KB)$ is a unit of measure. It equals about $100$ bytes.

A kilobyte $($KB$)$ ismama unit of measure. It equals about $1$ trillion bytes.

A kilobyte $($KB$)$ is a unit of measure. It equals about $1,000$ bytes.