The data are for a firm operating in perfect competition:

Output	Marginal Cost	Average Variable Cost	Average Total Cost
1	70	70	200
2	60	65	130
3	50	60	103.3
4	60	60	92.5
5	70	62	88
6	80	64.3	86
7	100	70	88.6
8	120	76.25	92.5

If the market price is $80, calculate the profit-maximizing level of output and profit or loss. Show your work.