A difference in which of the following would be an example of inequality in transaction costs as alluded to in lines 40-43？

A. Maximum amounts of loans extended by a bank to businesses in differenct areas
B. Fees charged to large and small investors for purchasing stocks
C. Prices of similar goods offered in large and small stores in an area
D. Stipends paid to different attorneys for preparing legal suits for damages
Exchange rates in dollars for currencies of different countries