Suppose that Japan wishes to use sterilized market intervention to devalue the yen. Japan's central bank would ____ yen and simultaneously_____Japanese treasury securities:

buy,buy

sell,sell

sell,buy

buy,sell

Can you please explain this question to me. I think the answer is Sell/Buy because ,bank increases the money supply into the market thus decreasing the currency value.Also by buying back the government securities there is an inflow of the money into the economy thus increasing the money supply and decreasing the currency value but I am not sure.