With reference to the Qutub Minar complex, consider the following statements:

1. It is a five-storeyed red brick tower built during the thirteenth century.

2. Its construction was started by Qutub-ud-din Aibak in 1193 and finished by Firoz Shah Tughlaq.

3. The Minar is engraved with fine arabesque decorations on its surface, mainly verses from the Quran.

4. It is declared a UNESCO World Heritage Site.

Which of the statements given above is/are correct?