Which control$($s$)$ would best mitigate the following threats?

a$.$ The hours worked field in a payroll transaction record contained the value $400$ instead of $40.$ As a result, the employee received a paycheck for $$6,257\mathrm{.}24$ instead of $$654\mathrm{.}32.$

b$.$ The accounts receivable file was destroyed because it was accidentally used to update accounts payable.

c$.$ During processing of customer payments, the digit $0$ in a payment of $$204$ was mistakenly typed as the letter $$O$.$ As a result, the transaction was not processed correctly and the customer erroneously received a letter that the account was delinquent.

d$.$ A salesperson mistakenly entered an online order for $50$ laser printers instead of $50$ laser printer toner cartridges.

e$.$ A $20-$minute power brownout caused a mission$-$critical database server to crash, shutting down operations temporarily.

f$.$ A fire destroyed the data center, including all backup copies of the accounts receivable files.

g$.$ After processing sales transactions, the inventory report showed a negative quantity on hand for several items.

h$.$ A customer order for an important part did not include the customer$$s address. Consequently, the order was not shipped on time and the customer called to complain.

i$.$ When entering a large credit sale, the clerk typed in the customer$$s account number as $45982$ instead of $45892.$ That account number did not exist. The mistake was not caught until later in the week when the weekly billing process was run. Consequently, the customer was not billed for another week, delaying receipt of payment.

j$.$ A visitor to the company$$s Web site entered $400$ characters into the five$-$digit Zip code field, causing the server to crash.

k$.$ Two traveling sales representatives accessed the parts database at the same time. Salesperson A noted that there were still $55$ units of part $723$ available and entered an order for $45$ of them. While salesperson A was keying in the order, salesperson B$,$ in another state, also noted the availability of $55$ units for part $723$ and entered an order for $33$ of them. Both sales reps promised their customer next$-$day delivery. Salesperson A$$s customer, however, learned the next day that the part would have to be back$-$ordered. The customer canceled the sale and vowed to never again do business with the company.

l$.$ The warranty department manager was upset because special discount coupons were mailed to every customer who had purchased the product within the past $3$ years, instead of to only those customers who had purchased the product within the past $3$ months.

m$.$ The clerk entering details about a large credit sale mistakenly typed in a nonexistent account number. Consequently, the company never received payment for the items.

n$.$ A customer filled in the wrong account number on the portion of the invoice being returned with payment. Consequently, the payment was credited to another customer$$s account.

o$.$ A batch of $73$ time sheets was sent to the payroll department for weekly processing. Somehow, one of the time sheets did not get processed. The mistake was not caught until payday, when one employee complained about not receiving a paycheck.

p$.$ Sunspot activity resulted in the loss of some data being sent to the regional office. The problem was not discovered until several days later when managers attempted to query the database for that information.