Final answer:
The CAN-SPAM Act requires that any commercial e-mail must contain an opt-out mechanism.
Step-by-step explanation:
The legislation that requires any commercial e-mail to contain an opt-out mechanism is the CAN-SPAM Act. This law was enacted by the United States Congress in 2003 as a way to regulate commercial e-mail and prevent unwanted spam messages. The CAN-SPAM Act requires that commercial e-mails provide recipients with a clear and conspicuous way to opt out of receiving future messages.