Answer:
C

Explanation:
Based on how the line slopes, it is negative. The best way I can remember how to tell if a function is negative or positive is to read it like a book. If the left-most point of the line is above the right-most point, it is negative, such as is the case here. If the left-most point is below the right-most point, then it is positive.
Having determined that it is negative, A is eliminated. It also intersects the y-axis at -3, which eliminates D. To figure out how much it slopes, figure a point where the line cleanly goes through a point on the graph, such as (0,-3).
Using (0,-3) as a starting point, count how many points, or squares, on the graph, it takes to get to the next intersected point along the x-axis. Once you have that x-axis point, do the same thing along the y-axis.
In this example, you would go to the right (positive) 3 points, then down (negative) 4. The negative makes the m variable in the function
a negative. This function is also a fraction due to how for every 3 points moved to the right, it goes down by 4 if that makes any sense.
Anything that goes right and up is positive, while anything left and down is negative.