A class is having their picture, taking the photographer positions himself 21 feet from the center of the row of students. When the photographed for looks at the last student either in the row, the photographer must turn 45 degrees from the center in each direction, as shown in the diagram. Which is the best estimate of the length of the row of students? A-21 feet
B-24 feet
C- 30 feet
D- 42 feet