Answer:
y = -5/3 x + 40
Explanation:
The general form is y = ax + b, where a is the slope and b is the y intercept.
So immediately you can see that b must be 40, since the line crosses the y axis at 40.
The slope can be calculated by finding two "nice" points on the line that are also grid lines.
How about (0,40) and (6, 30).
Then, calculate the slope by dividing the y difference by the x difference:
(30-40)/(6-0) = -10/6 = -5/3
So C must be the answer.