Paralegal Susan Arrives at Her Office at 9:00 A

Paralegal Susan arrives at her office at 9:00 A.M.Every morning on arriving in the office, Susan normally checks her personal calendar for the day's court filing deadlines.Today, however, the secretary is out sick and Susan must man the phones and word processor for her.Susan forgets to check her calendar until the end of the day.As a result, she fails to file an important document with the court on behalf of her supervising attorney.Which ethical rule has been breached?

A) The duty of client confidentiality
B) The work product doctrine
C) The conflict of interest rule
D) The duty of competence