Corrections of errors

The only approach it to look at each of the possible answers separately and decide whether the error makes the debits bigger by 800 or not. If you need then make up little t-accounts to help you. For example, answer D: petty cash is a debit balance because it is an asset. If it is omitted then the debits will be too small (rather than too big) - so it is not D :-)

No - you are not asked to correct the mistakes. You just need to think through each of them in the way I wrote about D, and decide which one of them will make the debits 800 more than the credits.

Great :-)