The IRS will charge interest on late or unpaid taxes, regardless of cause. The period covered always begins with the original due date of the return 7/15 , and ends with the receipt of payment by the IRS. You may incur interest expenses for late filing, or simply for making a mathematical error on your tax return.
so use 3. and make the payment immediately so it's paid on 7/30. other methods will result in IRS receipt at a later date. you do not reflect this on the return. there will be a balance due to which the IRS will add the interest 5% penalty for late payment - amount unpaid on 7/15 and then subtract the payment. you will get a bill for the rest
