From here we already know it's c because that's the only option with 2/5 as slope but for future reference, I will tell you how to find y-intercept from here.
we have the incomplete equation y=2/5x+b because we have only found the slope so far, next, all you need to do plug in an x value and the corresponding y value from the table into the equation: -3=2/5(-10)+b -> -3=-4+b -> b=1 now we have the y-intercept and we can write the full equation.