Question: The Tucker Company sells three chemicals: petrol, septine, and tridol. Petrol is the company's product with the highest per-unit contribution margin, and tridol has the lowest per-unit contribution margin. Which one of the following events will always result in a decrease in Tucker's overall break-even point?
a.) The installation of a new computer-controlled machine and the subsequent layoff of assembly line workers
b.) A decrease in tridol's selling price
c.) An increase in anticipated sales volume of petrol relative to sales of septine and tridol
d.) An increase in petrol's raw material cost