The graph below shows a line of best fit on data collected on the cost of a cruise in relation to the number of extra activities added to the cruise.
<--JJ Jan2016--!>
The equation of the line of best fit is as shown below.
What does the y-intercept of this line represent?
A.
the number of activities added
B.
the total cost of all activities
C.
the cost per activity
D.
the cost of the cruise before adding any activities