Answer:
A
To ensure that Susan no longer has access without erasing her files I'll take the following steps:
B
The benefits that accrue to retaining her information will depend on the value of information that her account possesses. As the former executive IT personnel, this is most likely the case.
In the long run, the safest thing to do might be to just back up all information she created and had access to to a remote storage or data warehouse.
Cheers!