Sales Cost of sales Year 2 $170,000 135,000 Year 1 $130,000 105,000 Gross profit $ 35,000 $ 25,000 Based on the common-sized income statements for Years 1 and 2 (above), calculate the percentage increase or decrease in cost of sales from Year 1 to Year 2. Oa. Decrease of 2.1% Ob. Increase of 1.4% Oc. Increase of 2.1% Od. Decrease of 1.4%