A company produces 13,800 units of which 400 are spoiled units because the process, even though carefully and efficiently executed is unable to produce good units 100% of the time. Another 120 units are spoiled because machines broke down and there also were operator errors. What is the normal spoilage rate (round to two decimal places)

A. 3.77%

B. 3.01%

C. 2.9%

D. 0.87%