Calculate the monthly finance charge for the credit card transaction. Assume that it takes $10$ days for a payment to be received and recorded, and that the month is $30$ days long. $($Round your answers to the nearest cent.$)$

$$8,000$ balance, $15\%,$$$70$ payment

$($a$)$ previous balance method

$

$($b$)$ adjusted balance method

$

$($c$)$ average daily balance method $