$P$ Is a Point on the Unit Circle, And $Q$ And $R$

Multiple Choice

$P$ is a point on the unit circle, and $Q$ and $R$ lie on the ellipse shown below. The equation of the ellipse is given by $\frac{x^{2}}{4}+y^{2}=1$ . What is the $x$ -coordinate of $Q$ ?

A) $2 \cos \theta$
B) $2 \sin \theta$
C) $\cos \theta$
D) $\sin \theta$