Answer: 3
You can find slope by using the 'rise over run' method. Find 2 clear points and count the number of units between those points, across the x axis and up the y axis. You should have 3/1 (y/x) as your slope.
Jack had b boxes. Then he got 4 more. That is equal to:

On Wednesday, half the boxes were destroyed. To find half the amount, you can divide by 2, which is equal to:

Choice C matches the answer. Your answer is C