[单选题]
Three vectors, expressyubf7b7ap ago2j+81m vr 1p+oed in Cartesi(r, *6znpl6sv(kt q soan coordinates, are S = (-3.5,+4.5) T = (0,-6.5) U = (+5.5,-2.5) What is the angle of the resultant vector S + T + U measured from the positive x axis?
A. $24^{\circ}$ above
B. $24^{\circ}$ below
C. $66^{\circ}$ above
D. $66^{\circ}$ below
