Email marketing refers to a network marketing method that delivers valuable information to target users via email on the premise of the user's prior permission. "Email marketing has three basic elements: based on user permissions, passing information through email, information It is valuable to users. If one of the three elements is missing, none can be called effective email marketing. According to the above definitions, Which of the following are valid email marketing items:. ['Xiao Wang became a member publication of a brand product in 2002. One year after the membership period expires, Xiao Wang decides to withdraw from the membership, but he fails to do so on the Internet, and the product continues to send information.', 'Xiao Li registered a free email address on a portal site, and stated that he was willing to receive information about health care and sports games when registering. After using the email address, the website often sent information about health care and product discounts to his email address.', 'Xiao Zhao Cao Jing left an address for a certain manufacturer, hoping that the other party would mail the relevant materials free of charge. Later, he received an email without the sender\'s name, address, identity, and the title was "Product Catalog. " He was afraid the email There is a virus and it was deleted without opening it.', 'Xiao Gao received an email with the title: ‘Free gift card, direct consumption’. After opening it, he found that the recipient ’s column had only one address, but it was not his own email address, and he was puzzled.']