B. cart B
Explanation:
The acceleration of each cart is given by Newton's second law:
[tex]F=ma[/tex]
[tex]a=\frac{F}{m}[/tex]
where F is the force applied, a is the acceleration and m is the cart's mass.
The force F applied is the same for the two carts, however the mass of cart A (mA) is twice than the mass of cart B (mB), so we can rewrite the two accelerations:
[tex]a_A = \frac{F}{m_A}=\frac{F}{2 m_B}[/tex]
[tex]a_B = \frac{F}{m_B}[/tex]
we see that the acceleration of cart B is twice the acceleration of cart A, therefore cart B will move faster and will win the race.
