If MC is rising, there is nothing in particular one can conclude about ATC or AVC rising or falling. However, if MC is falling , we can conclude that ATC and AVC must be falling. If the price does not rise significantly, and the firm cannot lower its costs, it should shut down in the long run. Accounting profit is the profit reported by the normal rules of accounting. Normal profit is the usual profit an investor can expect to make in a business, taking into account the amount of investment and the level of risk.
Economic profit is the amount by which accounting profit exceeds normal profit.
We only know two points on the supply curve. If this is -0.5, it means that if quantity goes up by a certain percentage, price has to go down by twice that percentage. This is the same as MR being negative. If she lowers the quantity, the price will go up, cost will go down, and thus total revenue will increase. This is clearly a case of price discrimination.