5. (4 points) The state of an ideal gas is changed in a closed path $1 \to 2 \to 3 \to 4 \to 1$. Which of the following is true about work done on the gas?
$W_{1\to 2} > 0$, $W_{2\to 3} = 0$, $W_{3\to 4} < 0$, $W_{4\to 1} = 0$
$W_{1\to 2} < 0$, $W_{2\to 3} = 0$, $W_{3\to 4} = 0$, $W_{4\to 1} > 0$
$W_{1\to 2} < 0$, $W_{2\to 3} = 0$, $W_{3\to 4} > 0$, $W_{4\to 1} = 0$
$W_{1\to 2} = 0$, $W_{2\to 3} > 0$, $W_{3\to 4} = 0$, $W_{4\to 1} < 0$
$W_{1\to 2} = 0$, $W_{2\to 3} < 0$, $W_{3\to 4} = 0$, $W_{4\to 1} > 0$
