Consider the following statements about the Perpetual bonds:

1. They are fund-raising instruments that do not carry any maturity date as bonds usually do.

2. They offer to pay their buyers a coupon or interest at a fixed date for perpetuity.

3. Investors can get the principal back by selling the bond in the secondary market, or when the issuer decides to redeem the bonds.

4. These bonds have an obligation to pay both interest and debt.

How many of the above is/are incorrect?