Right choice is (a) affix
Explanation: The affix plugin allows an element to become affixed (locked) to an area on the page. It is often used with navigation menus or social icon buttons, to make them “stick” to the specific area while scrolling up and down the page. An alert message box is created on window by alert element. popover box displays when user clicks on that element. Tootlip is popoup box which appears when user hovers the mouse pointer on it.
