Which of the following is the best way to compensate for the lack of adequate segregation of duties in a small organization?

The current scenario is dangerous and high risk of frauds,  mis appropriation and mis use of inherent powers.

 

To overcome such issues is (d) to let the Management is aware of this issue and to provide extra over sight in this area and then (b) Rotate the personnel every2-3 years to detect any fraud which may have occured in near past. 

The best answer seems to be A, the worst is B.

Regardless of the circumstances for each case related to this risk (lack of adequate segregation of duties in a small organization), I believe that option A and option D on general could help to mitigate this risk.
However, I believe that there are other effective and efficient steps could also help in metigating this risk such as :
1- Use existing employees from other departments to do tasks that don't need for technical skills such as (data entries, Mail receipt and distribution, Payments and receipts).

2- Use existing employees from other departments to do some internal controls such as periodic and surprise cash & stock counts.

(A) is correct

Option a

The external auditors should discover the lack of segregation of duties by themselves without the disclosure  by the client! ! I would rephrase option B to read : rotating instead of replacing! 

d

d. Allowing for greater management oversight of incompatible activities