el><input type="radio" name="q7" value="3"> d) None of the above</label></li>
            </ul>
            <div class="feedback" id="feedback7"></div>
        </div>

        <div class="question">
            <p>Which of the following statements is true about the least-squares objective function \( f(x) = \|Ax - b\|_2^2 \), where \( A \in \mathbb{R}^{n \times d} \) has full column rank and \( b \in \mathbb{R}^n \)?</p>
            <ul class="options">
                <li><label><input type="radio" name="q