If `cos 3theta+sin3theta+(2sin2theta-3)(sin theta-cos theta)gt0`, then `theta` lies in
A. `(2n pi-(3pi)/(4),2n pi+(pi)/(4)),n in Z`
B. `(2n pi-(pi)/(2),2n pi+(pi)/(6)), n in Z`
C. `(2n pi-(pi)/(3),2n pi+(pi)/(3)), n in Z`
D. `(2n pi-(pi)/(4),2n pi+(3pi)/(4)), n in Z`