Which controls would best mitigate the following threats?

a) posting the amount of a sale to a customer account that does not exist.

b) a customer entering too many characters into the five digit zip code while making an online purchase, causing the server to crash.

c) An intern's pay rate was entered as $150 per hour, not $15 per hour.

d) Approving a customer order without the customer's address so the order was not shipped on time.

e) Entering the contract # of a critical contract as 13688 instead of 16388m which is a serious mistake for the company.