Answer:
Option B- The new balance is $4365.63
Explanation:
Given : Brian's statement shows a previous balance of $4248.64, a payment of $250, and new transactions totaling $326. His APR is 12.3% .
To find :  What is his new balance? 
Solution : 
Previous balance = $4248.64
Payments = $250
First we find the unpaid balance,
Unpaid balance = Previous balance - Payments 
 = $4248.64 - $250
Unpaid balance = $3998.64
Rate of interest= 12.3%=0.123
Now, we find the finance charge
Finance charge = Finance rate × Unpaid balance
Finance charge = 

Finance charge = $40.986
New balance = Unpaid balance + finance charge + new transaction
New balance = $3998.64 +$40.986+ $326
New balance =$4365.626
Therefore, Option B is correct.
The new balance is $4365.63