Two particles with equal charge experience a force of 10 nN when they are 30 cm apart. What is the magnitude of the charge on each particle?

a. -5.8 × 10⁻¹⁰ C
b. -3.2 × 10⁻¹⁰ C
c. +3.2 × 10⁻¹⁰ C
d. +1.4 × 10⁻⁵ C