The integral \(\frac{1}{{2\pi }}\mathop \smallint \limits_0^{2\pi } \sin \left( {t - \tau } \right)\cos \tau d\tau\) equals to

The integral \(\frac{1}{{2\pi }}\mathop \smallint \limits_0^{2\pi } \s

1.	The integral \(\frac{1}{{2\pi }}\mathop \smallint \limits_0^{2\pi } \sin \left( {t - \tau } \right)\cos \tau d\tau\) equals to
A.	sin t cos t
B.	0
C.	\(\frac{1}{2}\cos t\)
D.	\(\frac{1}{2}\sin t\)
Answer» E.