Ena Sharples opened a retail shop on January $1.$ She invested $$10,000$ of her own money. She rented a store for $$2,000$ per month, paying first and last month's rent on January $1.$ She bought store fittings for $$5,000$ in cash. She bought goods for resale at a cost of $$10,000,$ on credit, payable on February $15.$ She incurred other expenses of $$1,000$ in January, all of which were paid for in cash. Her cash sales were $$15,000,$ and she also sold $$2,000$ on credit, which she expects to collect by the end of FebruaryAt the end of January her inventory had a cost of $$3,000.$ Amortization on the store fittings is estimated at $$100$ for the month Question The operating profit as $\%$ of sales for January was $($accurate to one decimal place$)$

a$)$none of these

b$)33\mathrm{.}8\%$

c$)75\mathrm{.}0\%$

d$)58\mathrm{.}8\%$

c$)40\mathrm{.}6\%$