What is the difference between a preventive control and a detective control? Which of the following are detective, rather than preventive, controls? Please select all that apply.

a. Entering an access code in addition to a password while logging into a banking website

b. Requiring two authorizing signatures for all checks/ electronic funds transfers over a certain dollar threshold

c. Preparing a bank reconciliation

d. Doing a quarterly physical count and observation of the items in a gift shop's inventory