Explain the use of a pull-up resistor in an active-low input scenario.

• A. The pull-up keeps the input high when the sensor is inactive; when the sensor activates and pulls the input low, the logic reads a low state.
• B. The pull-up keeps the input low when the sensor is inactive.
• C. The pull-up has no effect on the input state.
• D. The pull-up forces the input high only when the sensor is active.

Answer: (A)