Which control procedure would be most effective in addressing the

Which control procedure would be most effective in addressing the following problems?
a. When entering a journal entry to record issuance of new debt, the treasurer inadvertently transposes two digits in the debit amount.
b. The spreadsheet used to calculate accruals had an error in a formula. As a result, the controller’s adjusting entry was for the wrong amount.
c. The controller forgot to make an adjusting entry to record depreciation.
d. A sales manager tipped off friends that the company’s financial results, to be released tomorrow, were unexpectedly good.
e. The general ledger master file is stored on disk. For some reason, the disk is no longer readable. It takes the accounting department a week to reenter the past month’s transactions from source documents in order to create a new general ledger master file.
f. The controller sent a spreadsheet containing a preliminary draft of the income statement to the CFO by e-mail. An investor intercepted the e-mail and used the information to sell his stock in the company before news of the disappointing results became public.
g. A company’s XBRL business report was incorrect because the controller selected the wrong element from the taxonomy.
h. Instead of a zero, an employee entered the letter o when typing in data values in an XBRL instance document.