2017SD Q2(a) impact on WACC

I do not know how you calculated 8.86% because the question says (in note 3) that the current WACC is 12%. When part (a) asks for the impact on the WACC, I would actually have written there that it has fallen from 12% to 9.93%. However the examiners answer has chosen to mention it in his answer to part (b) instead. It doesn't matter for the marks where you chose to mention it.