Answer:
C
Because of the markings showing equal length lines 7x + 4 is double 4x or 48 is three times the length of 4x
Either solve 7x + 4 = 8x
4 = x
Or solve 48 = 12x
Substitute back in to 7x + 4 ......MN = 7 x 4 + 4 = 32