Answer
The statement is false.
Work Step by Step
Remember that each ionization process only caters for the removal of only one electron from the atom or ion.
That means the third ionization also only removes just 1 electron from the atom. It in fact removes 1 electron from the ion that has already lost 2 electrons before the ionization process.
Therefore, the third ionization energy is the energy needed to ionize another electron from an ion, the neutral atom of which has already lost 2 electrons before. The statement is false.