correct answer C

Right answer is C !
Source: https://help.salesforce.com/s/articleView?id=sf.mc_es_how_a_subscriber_opts_out.htm&type=5
"When the subscriber clicks the link, the system looks up which list the email was sent to and sets the subscriber's status to "Unsubscribed" for that list. If the email was sent to multiple lists the subscriber is on, the system unsubscribes the subscriber from all lists.
Meanwhile, the subscriber's browser displays a message that the unsubscribe action was successful and gives the subscriber options to resubscribe or manage other subscriptions."