Answer:
(B) 
 for any integer k.
 for any integer k.
Explanation:
The given function is:

We have to find the zeroes of the given function, thus we have
In clockwise direction, the zeroes of 
 are
 are 
 and
 and
In counterclockwise direction, 
 , thus
, thus
in general, the zeroes of the given function is 
 for any integer k.
 for any integer k.
Thus, option B is correct.