B makes the most sense because calculated acceleration does not take into account friction (unless stated to do so) so calculated will be higher than actual. Also, since she is pulling in the same direction and no other force is pulling in the other direction I do not know if other options make sense. This is my opinion go with your gut!
Explanation:
Friction always acts in the direction opposing motion. This means if friction is present, it counteracts and cancels some of the force causing the motion (if the object is being accelerated). That means a reduced net force and a smaller acceleration
