An isosceles trapezoid-shaped cardboard with a height of 30 units has an upper base length of 20 units. When this cardboard is cut along a line parallel to the lower base, reducing the height by 12 units, it is observed that the lower base length decreases by 6 units.
Accordingly, what is the area of the new cardboard obtained in square units?
A) 363
B) 385
C) 441
D) 450
E) 464