A Constant Electric Field Is Present Throughout a Region

A constant electric field is present throughout a region of space that includes the plane bounded by the x and y axes and the lines x = 30 cm and y = 50 cm. The electric flux through the plane's surface, in N ⋅ m²/C, is

A) 0.
B) 0.25.
C) 25.
D) 50.
E) 100.