Option 1: Pascal (Pa) is a standard unit of pressure in the International System of Units (SI). It`s defined as one newton per square meter.

Option 2: N/m^2 is also a unit of pressure. It`s synonymous with the Pascal, as pressure is defined as force (which is measured in newtons) per unit area (measured in square meters).

Option 3: J/m^2 is not a unit of pressure, this is why it is the correct answer. This is the unit of energy density, derived by dividing energy (measured in joules) by an area (measured in square meters).

Option 4: Bar is a non-SI unit of pressure, equivalent to 100,000 Pascals or 0.9869 atmospheres.