If \( z \) is a complex number such that \( |z| \ge 1 \), then the minimum value of \(\displaystyle \left| z + \frac{1}{2}(3 + 4i) \right| \) is:
\( \dfrac{5}{2} \)
\( 3 \)
\( \dfrac{3}{2} \)
\( 2 \)
