3. If the point $(x, y)$ lies on the ellipse $4(x-2)^{2}+y^{2}=4$, then the minimum value of $\frac{y}{x}$ is
A. 1
B. $-\frac{2}{3} \sqrt{3}$
C. -1
D. None of the above
3. B Hint: Let $\frac{y}{x}=k$, substitute $y=k x$ into the ellipse equation, and use the “$\Delta$” method.

