The regression equation given to us is y = 0.5x + 1.3
It is in the form y = mx+b m = 0.5 is the slope b = 1.3 is the y intercept
The slope of 0.5 indicates that each time x increases by 1, the value of y will increase by 0.5 (since 0.5 = 0.5/1)
Translate this into the context of the problem and that means "for every extra person attending (x), the prep time increases by roughly 0.5 hours" which is what choice C is saying, well a paraphrase of it anyway.
