which one of these types is the strongest firewall

[CISSP_Candidate]

Q. Which one of these is the strongest type of firewall

a.Packet Filtering Firewalls
b. Proxy Servers
c. Application Gateway
d. Circuit Filtering
e. Personal Firewall.

Can somebody arrange them in proper order from strongest to weakest ?
and also explain which one is the strongest type and why ?

[Jescoi]

It is hard to compare firewalls because they are picked depending on requirements and budget constraints.

e. Personal Firewall. This can be customized at a personal level, depending on requirements of the system running it. Runs on the application layer.
c. Application Gateway. Works at the application layer, providing lots of granuality
b. Proxy Servers - Appl layer, though has disadvantage that it requires a proxy for each type of application.
d. Circuit Filtering - Works at session layer
a. Packet Filtering Firewalls - ACL based firewall. Stateful firewalls are better than this and Dynamic state firewalls even better.

I would also add that kernel proxy firewall is better than all these mentioned, since it inspects all layers and is quick since it works in the kernel of the OS.