Dr Bad Debt Expense Cr Allowance for Doubtful debts
The transactions you list above are the common trick- wrong answers. (‘Distractors’ in ACCA jargon).
‘Specific allowance’ means we go through our list of debtors and find individual accounts that are higher risk (e.g. over 90 days late) than the others.
These get a ‘specific allowance’ at a higher rate.
The remaining accounts get lumped together, and then they get the ‘general allowance’ rate.
Either way, the debits and credits are the same. They are just at different rates.