A Consumer Interest Group Is Interested in Comparing the Speed

A consumer interest group is interested in comparing the speed of four different desktop printers; four different documents are used for the experiment.Each test consists of randomly assigning one printer to one of the documents.The document is printed and the time to print in seconds is recorded.Each printer/document combination is tested.How many degrees of freedom does the treatment sum of squares have? How about the error sum of squares?

A) df-treatment = 3; df-error = 15
B) df-treatment = 4; df-error = 15
C) df-treatment = 3; df-error = 13
D) df-treatment = 3; df-error = 12
E) df-treatment = 4; df-error = 12