Respuesta :

To get the distance DC we proceed as follows:
AB-CD
=11-3
=8 
BC=15
hence using Pythagorean theorem
c²=a²+b²
c=DC
a=BC
b=8
thus
c²=15²+8²
c²=225+64
c²=289
thus
c=√289
c=17 units

Answer: B. 17 units