Pls help im hopeless




Points B and C lie on segment AD as shown below. Segment AD is 32 units long, segment AC is 23 units long, and segment BD is 27 units long. How many units long, if it can be determined, is segment BC?

________________________________ A B C D

A. 21
B. 18
C. 9
D. 4
E. Cannot be determined from the given information.​