Which of the following statements is correct for any closed loop system ?

All the co-efficients can have zero value
All the co-efficients are always non-zero
Only one of the static error co-efficients has a finite non-zero value
None of the above

The correct answer is: D. None of the above

The co-efficients of a closed loop system can be zero or non-zero, depending on the specific system. In general, there is no guarantee that any of the co-efficients will be zero.

Option A is incorrect because it is possible for some of the co-efficients to be zero.

Option B is incorrect because it is possible for some of the co-efficients to be zero.

Option C is incorrect because it is possible for more than one of the static error co-efficients to have a finite non-zero value.

In conclusion, the correct answer is: D. None of the above.