Definetely Stegoceras

Easily Pentaceratops because I like it and it would totally be able to craft a RPG to kill Brachiosaurus

Australotitan has a weight advantage against Brachiosaurus.

Stegoceras is the fastest and could easily dodge all the attacks

XD

But can it attack the others?

Apart from using its laser cannons and bombs, I mean.

If it builds up enough momentum it could deal devastating damage

XD