An ideal gas trapped in a cylinder expands while its pressure increases. The starting point for this process is labeled A$,$ and the end point is labeled B in the graph of pressure versus volume shown below.

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Which of the following correctly describes what happens to the pressure?

Group of answer choices

Pf $=3$ Pi

Pf $=2$ Pi

Pf $=$ Pi

Pf $=1/3$ Pi