The answer is option C "Dancers and singers are needed for the play." Options A, B, and D in order for these options to be complete sentences they need more information for example option D 'To really appreciate its beauty' needs some more information added to it so it is a complete sentence so... 'To really appreciate its beauty, you need to focus on the key aspects of the flower to really see it's beauty.' Other options (besides C) are examples of run-on sentences.
