Answer:
 option (B) $4,725.89
Explanation:
Given:
Annual payment = $12,600.47
Principal amount = $72,000
Interest rate = 8.15% = 0.815
Now,
Principal amount paid = Annual payment - Interest paid
and,
Interest paid = Principle × interest rate
Balance = Principal amount - principal paid
Thus,
For year 1
Interest paid = 72000 × 0.815 =  $5,868
Principal amount paid = $12600.47 - $5,868 = $6732.46  
Principal remaining = $72,000 - $6732.46 = $65257.53
For year 2
Interest paid = principal remaining × Interest rate
Interest paid = $65257.53  × 0.815 =  $5319.30         
Principal amount paid = $12600.47 - $5319.30 = $7281.17          
Principal remaining = $72,000 - $7281.17 = $57986.36
For year 3 
Interest paid = principal remaining × Interest rate
Interest paid = $57986.36  × 0.815 =  $4725.89  
Year	Annual payment   interest paid   principal paid     Balance
  1             $12600.47             $5,868             $6732.46        $65257.53
  2                $12600.47             $5319.30         $7281.17          $57986.36
  3                $12,600.47            $4725.89  
Hence, 
the correct answer is option (B) $4,725.89