In the case, it states that she is dissatisfied with the frequency of rebalancing required and the amount of transaction cost. So for the fist part of question A My advantages where 1- gives a more stable efficient frontier therefore less rebalancing. 2- since their is less rebalancing their will be less transaction costs. However the cfa guideline answer has both these reasons under one advantage. These two issues can be seen independently, no?
Also, what do you usually write down for a question that asks you to discuss? Is it the same as explain or should we go more into details?