Step 1: Rewrite the equation of the ellipse.
We start by completing the square for both \( x \) and \( y \) terms in the equation:
\[
y^2 + 4x^2 - 12x + 6y + 14 = 0
\]
Rewrite the equation in standard form of the ellipse:
\[
\frac{(x - 3)^2}{a^2} + \frac{(y + 1)^2}{b^2} = 1.
\]
Step 2: Calculate the eccentricity.
The eccentricity \( e \) of an ellipse is given by the formula:
\[
e = \sqrt{1 - \frac{b^2}{a^2}}.
\]
After solving, we find \( e = \frac{\sqrt{3}}{2} \).
Step 3: Conclusion.
Thus, the eccentricity of the ellipse is \( \frac{\sqrt{3}}{2} \), corresponding to option (A).