For any two vectors $\vec{a}$ and $\vec{b}$, which of the following statements is always true ? (A) $\vec{a} \cdot \vec{b} \ge |\vec{a}| |\vec{b}|$ (B) $\vec{a} \cdot \vec{b} = |\vec{a}| |\vec{b}|$ (C) $\vec{a} \cdot \vec{b} \le |\vec{a}| |\vec{b}|$ (D) $\vec{a} \cdot \vec{b} < |\vec{a}| |\vec{b}|$