Graph B consists of a parabola that opens downward. If a parabola opens downward, the the coefficient of x will be negative.
<h2>More details:</h2>There is an easy way to tell whether the graph of a quadratic function opens upward or downward: if the leading coefficient is greater than zero, the parabola opens upward, and if the leading coefficient is less than zero, the parabola opens downward.