(i) All plots are themes → UniversalAffirmative (A–type). (ii) Some themes are fictions →Particular Affirmative (I–type). (iii) No fiction is a biography →Universal Negative (E–type). (iv) Some fictions are not biographies→Particular Negative(O–type). (3) Some letters are posts.All posts are digits. I + A⇒ I–type of Conclusion“Some letters are digits”. Conclusion I and ConclusionII form Complementary Pair. Therefore, either ConclusionI or Conclusion II follows.