(a) Explain why unilateral measures taken by a country cannot eliminate fully double taxation. (5 marks) (b) Some commentators have queried whether bilateral double taxation conventions relating to the taxation of income and capital are essential for the resolution of international tax problems. You are required to indicate whether, in your opinion, such double taxation conventions fulfil a useful purpose or purposes, and to examine the alternative approaches that might be adopted in relation to the problems that these conventions seek to address.