<Ul> <Li> Maintaining a weekly (mystery) "quota" of answers in the category . </Li> <Li> User wanting to become a TC must have more than or equal to 12% Best answers . </Li> <Li> User should be at least on level 2, although there have been claims that first - level users with TC Badge have been seen . </Li> <Li> User should concentrate only on one particular category to become a Top Contributor for that category . </Li> </Ul> <Li> Maintaining a weekly (mystery) "quota" of answers in the category . </Li> <Li> User wanting to become a TC must have more than or equal to 12% Best answers . </Li> <Li> User should be at least on level 2, although there have been claims that first - level users with TC Badge have been seen . </Li>

Which of these is not a service of a public library answers.com