For the free expansion of a gas,which of the following is true?

• A
  $Q = 0, W = 0$ and $\Delta E_{\text{int}} = 0$
• B
  $Q = 0, W > 0$ and $\Delta E_{\text{int}} = -W$
• C
  $W = 0, Q > 0$ and $\Delta E_{\text{int}} = Q$
• D
  $W > 0, Q < 0$ and $\Delta E_{\text{int}} = 0$