Two Equal Charges Are Separated by 5 Cm; the Repulsive $8.3 \times 10 ^ { - 7 } \mathrm { C }$

Two equal charges are separated by 5 cm; the repulsive force is found to be 2.5 N. The magnitude of one of the charges is

A) $8.3 \times 10 ^ { - 7 } \mathrm { C }$
B) - $7.6 \times 10 ^ { - 13 } \mathrm { C }$
C) $9.4 \times 10 ^ { - 7 } \mathrm { C }$
D) $6.9 \times 10 ^ { - 13 } \mathrm { C }$