The assignment content provides a brief overview of investment appraisal techniques used by the XYZ Company to select the best proposal among five given options. The main techniques employed are net present value, payback period, and profitability index. Based on these techniques, proposal D is found to be the most suitable option due to its highest NPV and acceptable payback period. However, it is recommended that the company should work towards improving its financial attractiveness, as all proposals have low profitability indices.