A trust is extinguished--
(a) when its purpose is completely fulfilled; or
(b) when its purpose becomes unlawful; or
(c) when the fulfilment of its purpose becomes impossible by destruction of the trust-property or otherwise; or
(d) when the trust, being revocable, is expressly revoked.
(a) when its purpose is completely fulfilled; or
(b) when its purpose becomes unlawful; or
(c) when the fulfilment of its purpose becomes impossible by destruction of the trust-property or otherwise; or
(d) when the trust, being revocable, is expressly revoked.