a) In an investment plan, the best timing for the sale of an asset should be when the asset is at its highest price. However, in the context of taxation planning, under what circumstances would a financial planner not advise a client to sell of their assets when prices are high? Also, explain the purpose of investment gearing and discuss briefly how it works.

b) Explain the concept and mechanics of a banker's acceptance and a repurchase agreement in detail.

c) Explain the concept of a callable bond. All things equal, do investors demand lower or higher returns from callable bonds? Why?