Refer to the Following Paragraph to Answer the Questions Below

Multiple Choice

Refer to the following paragraph to answer the questions below.
Sally Simpson conducted a content analysis study of the New York Times newspaper between 1915 and 2005. She first identified relevant articles involving government regulation of business. After finding 20,000 such articles, she systematically sampled articles with a sampling interval of 50. She then coded each sampled article based on the subjective meaning it expressed, as pro- or anti-government regulation using a 1 to 10 scale (1 = very anti-regulation, 10 = very pro-regulation) .
-How many articles did Ms. Simpson code?

A) 20,000
B) 4,000
C) 1,000
D) 400
E) insufficient information is given