Assertion (A): If an atom of polarizability a is placed in homogeneous field E, the energy stored is 0.5 aE2. Reason (R): Capacitance of an isolated conducting sphere R in vacuum is 4 p∈0 R farads.

• Both A and R are true and R is correct explanation of A
• Both A and R are true but R is not correct explanation of A
• A is true but R is false
• A is false but R is true