for finding the value, as follows is the method:
in 15th of march,his bank showing a balance of $56.75.in March 20, it was $87.37 (after 5 days)
$87.37 -$56.75.=$30.62, and $30.62+$5+$13.5=$48.87. Carlos deposited in his account between the March 15 and the March 20 the amount of $48.87. So the answer is the choice B.