If the initial pulse of 1000 is fed to shift register, after how many clock pulses does the sequence repeat?

If the initial pulse of 1000 is fed to shift register, after how many

1.	If the initial pulse of 1000 is fed to shift register, after how many clock pulses does the sequence repeat?
A.	15
B.	16
C.	14
D.	17
Answer» B. 16