We find that a bank's net interest margin is higher than its competitor. Which of the following are potential explanations for the difference?

A$)$ the bank's yield on earning assets is higher than its competitor

B$)$ the bank's earnings base is higher than its competitor

C$)$ the bank's cost rate is lower than its competitor

D$)$ the bank's percentage of interest bearing liabilities to total assets is lower than its competitor

E$)$ all of the above

F$)$ none of the above