John's breakeven point for September was $125,000. When he calculated the breakeven point for October it was only $115,000. What is the most likely reason for this change?

John's sales mix changed, likely with a higher percentage of sales in a department with a low contribution margin ratio.

John's fixed costs increased substantially from September to October.

John's variable costs increased substantially from September to October.

John's sales mix changed, likely with a higher percentage of sales in a department with a high contribution margin ratio.