Janice is at the surface of a swimming pool and record the following two measurements in feet on a number line -8 represents the depth of the water in the swimming pool. +12 represent the height of side at the pool

Part A: What does the 0 representing in this situation

Part B: Described the height of the slide in relation to zero

Part C Janice held a pole in the swimming pool. the bottom of the pole was at a depth of 4 feet. how should Janice mark the level of the bottom of the pole on the number line?

Btw I only need help with part c I just thought it be easier to show all of the parts