Barely had Laura sat down at her computer in her office when she was called away to deal with an unhappy customer  

A Because Laura was instructed to sort out the complaint of an annoyed customer, she had no time to sit down at her computer.

B Someone called Laura out of her office to try and sort out the problem of a dissatisfied customer just after she had sat down in front of her computer.

C An unhappy customer called Laura out of her office to deal with his complaint, just as she was getting into her seat in front of her computer.

D Laura was ordered to help resolve the problem of an upset customer before she was able to go into her office and sit down at the computer.