(1) What is the estimated final cost of the Medupi Power Station; (2) (a) what are the reasons for the costs escalating from the original R70 billion and (b) who is responsible for incurring these additional costs; (3) whether she plans on holding certain individuals or companies liable for the additional costs; if not, why not; if so, what are the relevant details; (4) when will the Medupi Power Station be operational?