A. \( \left\{\frac{3\pi }{4},\frac{7\pi }{4}\right\}\)
B. \( \left\{\frac{\pi }{3},\frac{5\pi }{3}\right\}\)
C. \( \left\{\frac{3\pi }{4},\pi ,\frac{\pi }{3},\frac{5\pi }{3}\right\}\)
D. \( \left\{\frac{\pi }{6},\frac{5\pi }{6},\frac{11\pi }{6}\right\}\)