Grocery stores often place similar types of cereals on the same shelf. The consumer is interested in knowing if sugary cereals are kept together or if sugar content in cereals vary from shelf to shelf. There are three shelves in a grocery store. Shelf one contains 15 sugary cereals, and shelves two and three each contain 7 sugary cereals. The MSE is found to be 16.93. What is the margin of error for a 90% confidence interval used to estimate the difference in mean sugar content for shelves one and three?

A) 1.584

B) 2.589

C) 3.098

D) 3.213

E) 3.249