Which of the following is wrong? In sequential structures:

1. Class C holders have higher prepayment risk protection than class A holders.
2. Class A holders have higher prepayment risk than class B holders.
3. Class B holders have equal prepayment risk protection as class C holders.
4. Class A holders have lower prepayment risk protection than class B holders and lower prepayment risk protection than class C holders.
5. Class D holders have higher prepayment risk protection than class B holders.