Answer: B. Only I, II and IV follow.
I. Some dogs are animals: From statement 1 (Some dogs are cats) and statement 2 (All cats are animals). Since some dogs are cats, and all cats are animals, it follows that 'Some dogs are animals'. Thus, Conclusion I follows.
II. No cat is a bird: From statement 2 (All cats are animals) and statement 3 (No animal is a bird). Since all cats are part of animals, and no animal is a bird, it means 'No cat is a bird'. Thus, Conclusion II follows.
III. All dogs being birds is a possibility: From statement 1 (Some dogs are cats). From statement 2 (All cats are animals). From statement 3 (No animal is a bird). This means the 'cats' part of dogs cannot be birds. If 'All dogs were birds', then the 'cats' part of dogs would also have to be birds, which contradicts 'No animal is a bird'. Therefore, it is NOT possible for all dogs to be birds. Thus, Conclusion III does not follow.
IV. Some animals are not dogs: From statement 1 (Some dogs are cats) and statement 2 (All cats are animals). This implies 'Some animals are dogs' (specifically, the cats). However, the set of 'cats' is a subset of 'animals'. It is not stated that all animals are cats. Therefore, there must be some animals that are not cats, and thus not dogs. Thus, Conclusion IV follows.
Therefore, only conclusions I, II and IV follow.