The correct option is (a) <div>
The best explanation: For grouping together related elements we use <div> element. Anything that lies outside of <footer>, <aside> or <content> elements can be considered as main content. E.g. <div class= “wrap”> <header> <h1> kitchen </h1> </div>. Grouping of related content together is done by <section> element. An introductory content lies in <header>. For grouping together set of one or more <h1> to <h6> element we use <hgroup> element.