Identify the function which represents a periodic motion

The function is said to be periodic if we can write it in to form of, $y=A\sin \left(\omega t+\varphi \right)$.

In the above options only we can write, $\sin \left(\omega t\right)+\cos \left(\omega t\right)$, in the form of, $\sin \left(\omega t\right)\cos \left(\frac{\pi }{4}\right)+\cos \left(\omega t\right)\sin \left(\frac{\pi }{4}\right)=1\times \sin \left(\omega t+\frac{\pi }{4}\right)$, so we can say that, $\sin \left(\omega t\right)+\cos \left(\omega t\right)$ is a periodic function.  $$