Why Do Decreases in Company Profitability Decrease in Direct Proportion

Why do decreases in company profitability decrease in direct proportion to the payroll expenses?

A) Because payroll represents a liability and an expense of the business.The higher payroll expenses are,the lower the profitability will be.
B) Because payroll represents an asset and an income of the business.The higher payroll income are,the higher the profitability will be.
C) Because payroll represents a liability and an expense of the business.The lower payroll expenses are,the lower the profitability will be.
D) Because payroll represents an asset and an income of the business.The lower the payroll expenses are,the higher the profitability will be.