nput type="radio" name="q1" value="0"> a) \( \nabla^2 f(x) \prec 0 \), for all \( x \in \mathbb{R}^d \)</label></li>
                <li><label><input type="radio" name="q1" value="1"> b) \( \nabla^2 f(x) \preceq 0 \), for all \( x \in \mathbb{R}^d \)</label></li>
                <li><label><input type="radio" name="q1" value="2"> c) \( \nabla^2 f(x) \succeq 0 \), for all \( x \in \mathbb{R}^d \)</label></li>
                <li><label><input type="radio" name="q1" value="3"> d) \( \nabla^2 f(x) \succ 0 \),