Comparative financial statements for Bent Stew Enterprises are shown below:

December 31

20142013

Assets

Current assets:

Cash $ 3,000 $ 800

Accounts receivable 8,500 6,000

Inventory 12,000 8,200

Prepaid expenses1,400900

Total current assets 24,900 15,900

Property, plant, and equipment, net 103,600 123,300

Intangible assets, net64,00047,000

Total assets $192,500 $186,200

Liabilities and Stockholders' Equity

Current liabilities:

Accounts payable $ 11,000 $ 12,000

Other current liabilities11,8003,200

Total current liabilities 22,800 15,200

Long-term debt120,000128,000

Total liabilities142,800143,200

Stockholders' equity:

Common stock 15,000 15,000

Additional paid-in capital 20,000 20,000

Retained earnings14,7008,000

Total stockholders' equity49,70043,000

Total liabilities and stockholders' equity $192,500 $186,200

Year Ended December 31

20142013

Sales $250,000 $ 230,000

Cost of goods sold164,000142,300

Gross margin 86,000 87,700

Operating expenses64,00054,000

Operating income 22,000 33,700

Interest expense7,5005,900

Earnings before income taxes 14,500 27,800

Income taxes7,8007,140

Net earnings $ 6,700 $ 20,660

Using vertical analysis, how would you best describe the change in the company's operating expenses from 2013 to 2014?

A. Operating expenses increased from 1.63% of net earnings to 9.55% of net earnings from 2013 to 2014.

B. Operating expenses increased by $10,000 from 2013 to 2014.

C. Operating expenses increased from 23.5% to 25.6% of sales from 2013 to 2014.

D. Operating expenses increased by 18.5% from 2013 to 2014.