the slope in y = mx + b form will be in the m position (the number before the x)
y = 2/5x ? 2..here the slope is 2/5.....a perpendicular line will have a negative reciprocal slope. All that means is " flip " the slope and change the sign.
2/5.....flip it....5/2...change the sign...-5/2...so we need a slope of -5/2.
answer C......y = -5/2x + (-3)