At a point P on a vector electric-field map, three previously measured contributions are known:
• 6N/C directed east
• 4N/C directed south
• 2N/C directed west
Which of the following is closest to the magnitude and direction of the net electric field at P?
a) 5.7N/C directed 45∘ south of west
b) 7.2N/C directed 34∘ south of east
c) 5.7N/C directed 45∘ south of east
d) 8.0N/C directed 45∘ south of east