Two metallic spheres of radii 1 cm and 3 cm are given charges of $-1 \mathrm{x} {10}^{-2} \mathrm{C} \mathrm{and} 5 \mathrm{x} {10}^{-2} \mathrm{C}$, respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is :

• A

  $4 \mathrm{x} {10}^{-2} \mathrm{C}$

• B

  $1 \mathrm{x} {10}^{-2} \mathrm{C}$

• C

  $2 \mathrm{x} {10}^{-2} \mathrm{C}$

• D

  $3 \mathrm{x} {10}^{-2} \mathrm{C}$