Statements: Some book are helmets.
Only copies are helmets.
Conclusion: I Some book sare copies
II all helmets are copies
III. All copies are helmets.
IV. Some copies are not helmets.

Options

A. I and III follow
B. Only III follows for ll follows
C. II and III follow
D. only I , II and either III or IV follows

Answer

D

Explanation

We know that propositions with .Only. are called exclusive propsitions and they can be conveted to A-type prepositions by interchanging the subject and the precdicate. Thus we have .. Only copies are heloments `.. to..` all helmeta are copies . Now some book are helmets + only copies are helmets = Some book are helmets + All helmets are copies =I+A=I= some book are cipies, thus I and II follows. Further, statements III and IV, beings A-O pair, form a complementary pair and hence at any time one of then must be true. Hence either III or IV also follows.