Query related to director

CA. Karan Karnani (CA, CS, MCOM, BBA) (110 Points)

14 August 2013  
Case -
A company having at present 6 directors 
1- appointed at the time of incorporation and not liable to retire by rotation. (MD) - A 
1- appointed at the time of incorporation and liable to retire by rotation - B 
3- C,D,E - appointed in october, 2012. And all liable to retire by rotation 
1- F- appointed in feb 2013. And liable to retire by rotation 
In this AGM, appointment of C,D,E and F needs to be regularised. As per section 260.
Also 2 out of 5 directors need to be retire by rotation as per section 255 
if i propose, B and C to retire.
Now my question is that is it correct that C who is to be regularised in the upcoming AGM, is also retiring by rotation at the same time. Can this be done simultaneously .? 
If no is it correct if i propose only B to retire by rotation .?
Note :- C,D,E,F. All are appointed as additional directors
Please help me out with proper explanation