In its 2013 annual report, Caterpillar Inc. reported the following (in millions):

2013 2012

Sales $55,656 $65,875

Cost of goods sold $40,727 $47,055

As a percentage of sales, did Caterpillars gross profit increase or decrease during 2013?

a. Gross profit increased from 26.8% to 28.6%

b. Gross profit decreased from 28.6% to 26.8%

c. Gross profit increased from 71.4% to 73.2%

d. Gross profit decreased from 73.2% to 71.4%

e. There is not enough information to answer the question.