To solve this problem, we need to evaluate the correctness of the given statements about Mycoplasma.$\newline$Statement I: Mycoplasma can pass through less than 1 micron filter size.$\newline$• Mycoplasma are known to be the smallest free-living organisms, typically around 0.2 to 0.3 microns in size.$\newline$• Due to their small size, they can indeed pass through filters with pore sizes less than 1 micron.$\newline$• Therefore, Statement I is correct.$\newline$Statement II: Mycoplasma are bacteria with cell walls.$\newline$• Mycoplasma are unique among bacteria because they lack a cell wall.$\newline$• Instead, they have a flexible cell membrane, which allows them to assume various shapes.$\newline$• Therefore, Statement II is incorrect.$\newline$Analyzing the options:$\newline$• Option 1: Both Statement I and Statement II are correct. This is incorrect.$\newline$• Option 2: Both Statement I and Statement II are incorrect. This is incorrect.$\newline$• Option 3: Statement I is correct but Statement II is incorrect. This is correct.$\newline$• Option 4: Statement I is incorrect but Statement II is correct. This is incorrect.$\newline$Therefore, the correct option is Option 3.