You are already given the formula and all the inputs it needs, so you only need to plug in the values.
In the formula

n is the number of mols, which you are given: 3. R is a constant, which value is given: 8.31 J(mol*K). Finally, you are given the temperature in celsius, which is 25, but you are reminded that to compute the same temperature in Kelvin you need to add 273, so you have

Now we're ready to plug the values in the formula:

So, the option that best approximate the real value is the second one, 18600.