Explanation:

The bodhisattva ideal is central to the Mahayana Buddhist tradition as the individual who seeks enlightenment both for himself and for others.

In non-Mahayana Buddhism, it usually refers either to Maitreya, the Buddha of the Future, or to the historical Buddha Gautama prior to his enlightenment.

Statement 2 and 3: A bodhisattva is literally a living being (sattva) who aspires to enlightenment (bodhi) and carries out altruistic practices.  Clearly 2 is correct. Bodhisattva delays achieving his own salvation to help all sentient beings on their path to it.