A

\[\{2k\pi + \frac{\pi}{6}\}\]

B

\[\{2k\pi + \frac{\pi}{3}\}\]

C

\[\{2k\pi + \frac{\pi}{4}\}\]

D

\[\{k\pi + \frac{\pi}{4}\}\]

E

\[\{k\pi + \frac{\pi}{2}\}\]