The function below models the correlation between the number of hours a plant is kept in sunlight (x) and the height (y), in mm, to which it grows: y = 4 + 2x

What does the slope of this function represent? (1 point)

Group of answer choices

The original height of the plant was 4 mm.

The original height of the plant was 2 mm.

The height of the plant increases by 2 mm for every hour of sunlight it receives.

The height of the plant increases by 4 mm for every hour of sunlight it receives.