Computer Inc $\%$ B) 45 $\%$ C) 450 $\%$ D) 34 $\%$ E) 23 $\%$

Computer Inc. uses a markup of $1260 on a computer system for which they pay $2800. What is the markup rate on this system?

A) 5 $\%$
B) 45 $\%$
C) 450 $\%$
D) 34 $\%$
E) 23 $\%$