The Schematic Diagram Above Illustrates a Carnot Engine $\to$ 2, 2 $\to$

The schematic diagram above illustrates a Carnot engine. Which two paths of the cycle is work done by the gas?

A) 1 $\to$ 2, 2 $\to$ 3
B) 2 $\to$ 3, 3 $\to$ 4
C) 3 $\to$ 4, 4 $\to$ 1
D) 4 $\to$ 1, 1 $\to$ 2
E) only 1 $\to$ 2