Consider the following statements.

1. Alauddin Khilji styled himself as the Second Alexander (Sikander-i-Sani).

2. Jalaluddin Khilji was the first ruler of the Delhi Sultanate to put forward the view that kingship should be based on the willing support of the government.

3. Iitutmish was the first Sultan who requested and obtained letters of investiture from the Caliph.

4. The token currency, 'tanka', introduced by Mohammad-bin-Tughlaq was made of bronze.

Which of the statements given above are correct?