All dogs are animals. Some animals are pets. Which of the following conclusions necessarily follows?
Correct: C
The middle term 'animals' is distributed in the first premise (All D are A) but undistributed in the second premise (Some A are P). This is the fallacy of the undistributed middle. We cannot draw any definite conclusion linking dogs and pets. 'Some dogs are pets' is not guaranteed. 'All pets are dogs' and 'No pet is a dog' are also unsupported. The syllogism is invalid as structured.