Melanie bought a house on 1 June 1986 for £3 1,000. The house was sold on 31 December 2017 for £173,000. Compute the chargeable gain arising in each of the following cases:

(a) Melanie occupied the house as her principal private residence throughout the period of ownership.

(b) Melanie occupied the house throughout her period of ownership with the exception of the period between 1 June 1993 and 31 May 1997 when she lived with a friend.

During this time the house stood empty.

(c) As (b) except that the house was let as residential accommodation during Melanie's absence.