SSC CHSL Model Paper 20

Two statements are given followed by three conclusions. You have to consider the given statements to be true even if they seem to be at variance with commonly known facts. You have to decide which of the given conclusions can definitely be drawn from the statement. Indicate your answer.
Statements: All rats are cats. No rats are dogs
Conclusion:
1. No cats are dogs
2. Some cats are not dogs
3. Some cats are dogs.