Given that:$\frac{2\sin \theta-\cos \theta}{\cos \theta+\sin \theta}=1$

$\implies2\sin \theta-\cos \theta=\cos \theta +\sin \theta$

$\implies \sin \theta=2\cos \theta$

$\implies \frac{\sin \theta}{\cos\theta}=2$

$\implies \tan \theta=2$

Option (C) is correct.