Answer
The 4th plot does not correctly represent Boyle's Law.
Work Step by Step
Boyle's law states that pressure and volume are indirectly proportional to each other. In other words, $P=$k\frac{1}{V}$ where $k$ is a positive number. However, the 4th graph does not depict this relationship as it displays k as a negative value which does not match up with Boyle's Law.
