A solid conducting sphere has a charge - 2Q and is surrounded by a neutral concentric hollow conducting spherical shell of double the radius. The potential difference between the solid sphere and the shell is V. The shell is, now given a charge - 3 Q; the new potential difference between them will be :

• A

  V

• B

  -V

• C

  0.5 V

• D

  -0.5 V