what is the difference between absolute position and fixed position? optionAAbsolute position places items relative to their current location, and fixed position places items relative to the closest positioned ancestor.optionBAbsolute position places items relative to the closest positioned ancestor, and fixed position places items relative to the viewport.optionCAbsolute position places items in the same position on the page no matter what the browser does, and fixed position places them relative to the browser window.optionDAbsolute position places items relative to the upper-left corner of the viewport, and fixed position places items relative to the lower-right corner of the viewport