In an application used to adjust the sound level of a music program, consisting of 100 equal units in the shape of a right triangle, the appearance of the application when the sound level is 60 units is given in Figure 1.
When the sound level is increased to 70 units as shown in Figure 2, the area of the green right triangle increases by 260 square units.
Accordingly, what is the height marked with ? in the appearance of the application in units?
A) 30
B) 35
C) 40
D) 45
E) 50