Explanation:

- Option 1: Galvanometer

- A galvanometer is an instrument designed to detect and measure small electric currents.

- It works by utilizing the torque on a coil in a magnetic field, allowing the movement to indicate the presence and direction of the current.

- This option is correct. Hence, a galvanometer is indeed the instrument that detects the presence of electric current.

- Option 2: Motor

- A motor converts electrical energy into mechanical energy.

- It is designed to produce motion rather than detect currents.

- Option 3: Generator

- A generator converts mechanical energy to electrical energy.

- Like a motor, it doesn't serve to detect currents.

- Option 4: None of the above

- This option does not apply as the galvanometer is a valid detecting device for electric current.