The correct option is
D Decreasing variable costs
Margin of safety is the level of sales over and above the break even sales.
Break even sales is having direct correlation with selling price and variable cost.
If variable cost decreases, break even level will improve and this gives more safety to the organization as margin of safety will also improve.
Example:
Case 1 Case 2
Selling Price Per unit Rs.10 Rs.10
Variable cost Per unit Rs.5 Rs.4
Contribution Rs.5 Rs.6
Fixed Cost Rs.3000 Rs.3000
Break Even Point = Fixed Cost 3000/5 3000/6
Contribution
Break Even Point in units = 600 500
Break Even Point in Rs. 6000 5000
Margin of Safety= Actual Sales-Break Even sales
10000-6000 10000-5000
=4000 =5000
It is evident that Margin of Safety increases if variable cost decreases.