And what is a #"mole"#? It is a counting number like #10#, or #12#, or #100#. One mole of stuff specifies #6.022xx10^23# individual items of that stuff.

Why should we use such an absurdly large number? It happens that if I have #6.022xx10^23# individual #""^12C# atoms, I have a mass of #12.00*g# precisely. The mole is thus the link between the (sub)micro world of atoms and molecules, which we can't see, with the macro world of grams, and litres, and kilograms, which we can measure in a lab.

So we have got #6.022xx10^23# #CO_2# molecules, and #22.4*L# of #CO_2# molecules at #"STP"#, and #0.44*g# of #CO_2#. In fact, #6.022xx10^23# #CO_2# molecules, and #22.4*L# of #CO_2# molecules at #"STP"#, have the same number of molecules by definition (and have a mass of #44*g#), and thus the same number of atoms.

This is not a good multiple choice question, because 2 answers are valid.