Two positive point charges q1=+4μC (at x=0) and q2=+6μC (at x=0.30m) are fixed on a straight line. A third charge q3 is to be placed at x=0.90m so that the net electrostatic force on q2 is zero. What should be the value of q3?
a) +8μC
b) −16μC
c) +16μC
d) +36μC