I don't really see a question here. Do you mean a transition in color? or in shape? whats the question?
The correct answer is letter C. The Apse. Apse is the more or less the central plan of the church and it is where the altar is located. It is a semicircular space containing the high altar.
Space clef westley beause of face
Perhaps a graphic designer. Posters and website design is part of this job, along with perhaps coming up with slogans.