Which of the following is not a single flower?

Sunflower is an inflorescence. It has a capitulum type of inflorescence. In this type of inflorescence tip of peduncle becomes broad, flattened concave or convex
(receptacle). On it small sessile flowers are found. These flowers are called florets. The florets which are present in the centre are small & called disc florets and
florets which are present at periphery are large & called ray florets, florets are arranged in centripetal order.