Question

Question #9c5cf

Answer 1

If it is able to extract at least `2J` from the water....

Explanation:

If I remember correctly the Heat Pump is like a fridge where instead of using...the food compartment you take advantage of the heat produces in the grid behind it to heat up the room.
Schematically:

You can supply heat `Q_h=3J` having used/extracted:
`Q_c+W=3J`