The Computer Fraud and Abuse Act (CFAA) primarily addresses unauthorized access to computers and networks, as well as certain types of computer-related fraud and abuse. Therefore, the option that would be most closely related to behavior protected under the CFAA is:
a person in another state accessing their bank account.
This scenario would typically involve accessing a computer system (the bank's system) for which the person has legitimate credentials. The CFAA would protect against unauthorized access, but accessing your own account is not considered unauthorized.
The other options (illegal downloading, advertising to children, and posting negative comments) do not fall under the protections offered by the CFAA.