Electrostatics

Bodies $P, Q, R, S$ are labelled as having charges $Q_P=0.5 \times 10^{-19} C, Q_Q=0.7 \times 10^{-19} C$, $Q_R=2.1 \times 10^{-19} C, Q_S=4.8 \times 10^{-19} C$ respectively.

Select the body having the correct charge.

[Given electronic charge $=e=1.6 \times 10^{-19} \mathrm{C}$ ]