Would each of the following increase, decrease, or have an in determinant effect on a firm’s breakeven point (unit sales)?

Question

a. An increase in the sales price with no change in unit costs.
b. An increase in fixed costs accompanied by a decrease in variable costs.
c. A new firm decides to use MACRS depreciation for both book and tax purposes rather than the straight-line depreciation method.
d. Variable labor costs decline; other things are held constant.