The least possible Venn diagram for the given statements is as follows,
Conclusion:I. All rats are dogs → False (From statement 2, No cats are rats then there will be no relation with dogs also ). II. Some dogs are rats → False (From statement 1,2, There is no relation for rats with respect to cats and dogs). Hence, Both Conclusions are Complimentary pairs. Thus, Both conclusions are False the answer is "Neither I nor II follows".