Use the following information to determine the change in income from operations for each situation if the company sells its products for $4 each. 

a. Contribution margin ratio of 35% and a 10,000 increase in sales units. 

b. Unit contribution margin of $2.10 and an increase of $20,000 in sales. 

c. Contribution margin of ratio of 30% and an increase in sales of $30,000.