This book explains how to approach and answer case studies.
3. How to approach a case study
3.10. E. Evaluation of alternatives and selecting the preferred one
If you have done the above properly, this should be straightforward. You measure the alternatives against each key decision criteria. Often you can set up a simple table with key decision criteria as columns and alternatives as rows, and write this section based on the table. Each alternative must be compared to each criteria and its suitability ranked in some way, such as met/not met, or in relation to the other alternatives, such as better than, or highest. This will be important to selecting an alternative. Another method that can be used is to list the advantages and disadvantages (pros/cons) of each alternative, and then discuss the short and long-term implications of choosing each. Note that this implies that you have already predicted the most likely outcome of each of the alternatives. Some students find it helpful to consider three different levels of outcome, such as best, worst, and most likely, as another way of evaluating alternatives.
After assigning weights and values to the various solutions you have thought about, select the one you like best and prepare to defend it. Show why the ideas you have thought about are superior and how they will work. If you have rejected other more obvious ideas, you may want to explain why.