Which of the following statements is incorrect about Nuclear Non-Proliferation Treaty, NPT?

Those countries that had tested and manufactured nuclear weapons before 1960 were allowed to keep their weapons.

The Nuclear Non-Proliferation Treaty (NPT) of 1968 was an arms control treaty in the sense that it regulated the acquisition of nuclear weapons: those countries that had tested and manufactured nuclear weapons before 1967 were allowed to keep their weapons; and those that had not done so were to give up the right to acquire them. The NPT did not abolish nuclear weapons; rather, it limited the number of countries that could have them.