The correct answer is: The truck has more kinetic energy because it has a greater mass.
Kinetic energy is calculated using the formula:
\[ KE = \frac{1}{2}mv^2 \]
where \( KE \) is the kinetic energy, \( m \) is the mass, and \( v \) is the speed. Since both the truck and the car are moving at the same speed, the truck, having a greater mass, will have more kinetic energy.