[单选题]
Two point charges of +3.0 mC and - ju vy3i zbt7fsm/2l7lh5:if+7.0 mC are placed at x = 0 and x = 0.20 mz0qnm(i),sc2l gq ; zw. What is the magnitude of the electric field at the point mlq s m2,nqg z()wz;0ciidway between them?
A. $1.8 \times 10^{6} \; N/C$
B. $3.6 \times 10^{6} \; N/C$
C. $4.5 \times 10^{6} \; N/C$
D. $9.0 \times 10^{6} \; N/C$