First Principles Thinking: Proprietary Information
A is correct. Standard IV(A) (Loyalty) prohibits taking employer property, including client lists, without permission. Client lists are proprietary assets. By downloading the entire firm list (not just what she might remember from memory), she misappropriated firm property. The intent (courtesy vs. solicitation) mitigates the severity but does not cure the violation of taking the property itself.
B is incorrect: While client data is confidential, the primary issue here between employee and employer is the breach of Loyalty/Ownership of records. Standard III(E) focuses more on keeping client data from third parties.
C is incorrect: Even for her own clients, the physical/digital list belongs to the firm. She generally cannot take the physical list without permission, though she may contact clients using information recalled from memory (jurisdiction dependent, but per Standards, the file is firm property).