Refer to the exhibit. 

Three calls are active on ephone 1. Assume ephone 2 will remain idle. How many additional calls can be placed from ephone 1? 

Answer options:

A. 0
B. 1
C. 2
D. 3
E. 5

C

As we can see max-calls-per-button set to 5 and 3 calls are active. So, 2 calls remain.