Three Spring Scales Are Attached Along a Straight Line as Shown

Multiple Choice

Three spring scales are attached along a straight line as shown. The scale on the left is attached to a wall. A force of 15 N is applied to the scale at the right. What is the reading on the middle scale?

A) 0 N
B) 45 N
C) 10 N
D) 5 N
E) 15 N