[单选题]
Three vectors, expressed in Cartesian coordidpwqv+ b 58h.di0.*y u8mcv ldr*ssp;nates,/vffbl5 l1ca .*5oktf+ 0oex3in2si f 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
