 x_0 \) is a global minimizer of \( f \) over \( D \) if and only if \( \nabla f(x_0) = 0 \)</label></li>
                <li><label><input type="radio" name="q3" value="3"> d) \( x_0 \) is a global minimizer of \( f \) over \( D \) if and only if \( \nabla^2 f(x_0) \succeq 0 \)</label></li>
            </ul>
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        </div>

        <div class="question">
            <p>Let \( f : \mathbb{R}^d \to \mathbb{R} \) be a continuously differentiable, convex 