In the figure, three particles are fixed in place with charges q_(1)=q_(2)=+1e and q_(3)=+3e. The distance a is 6.37μm. What is the magnitude of the net electric field at point P due to the particles?

A) 2.5 N/C
B) 5 N/C
C) 7.5 N/C
D) 10 N/C