Light Me Up Lamps Has Variable Expenses of 40% of Sales

Light Me Up Lamps has variable expenses of 40% of sales and monthly fixed expenses of $216,000. The monthly target operating income is $24,000. What is the monthly margin of safety in dollars if Light Me Up Lamps achieves its operating income goal?

A) $40,000
B) $440,000
C) $400,000
D) ($240,000)