please give the proper explaination i need your help.

1-If a company had a pure variable cost structure, what would be the relationship between contribution margin and net income, and what would be the magnitude of operating leverage?

2-For Marvin Company, the magnitude of operating leverage was 3.5 during the current year. Demonstrate what this magnitude of operating leverage would mean for the company's profitability by creating an example.

3-Select the incorrect statement regarding cost-volume-profit relationships for multiple products.

Multiple Choice choose one

a-For a company that sells many different products, the level of the break-even point is affected by the company's sales mix.

b-An increase in sales volume accompanied by a change in sales mix could cause a company's profits to decrease.

c-For a multi-product company, cost-volume-profit analysis can be done using the contribution margin ratio of the most profitable product.

d-None of these