Which of the following are correct statements? 1) In break-even analysis, there is usually an assumption that the sales mix of products sold will not change. 2) The contribution margin ratio is calculated by dividing the contribution margin by total fixed costs 3) Once the break-even point has been reached, net operating income will increase by the amount of the unit contribution margin for each additional unit sold. Items 1) and 3) are both correct. All of the above items are correct. Items 1) and 2) are correct. None of the above items are correct.