Statements : a All crooks are spooks.
b All books are jokes.
c. Some books are crooks.
Conclusions: I Some jokes are crooks.
II Some spooks are jokes.
III. Some crooks are jokes.
IV. Some spooks are books.

Options

A. I, II and III follow
B. II, III and IV follow and IV follow
C. I, III and IV follow
D. None of these

Answer

D

Explanation

(c) + (a) gives Some books are spooks [ `:.` I + A=I] which may be converted to conclusion IV. Converted form of (c) [which is: Some crooks are books] + (b) gives conclusion III. From conclusion III, we get conclusion I, on conversion. Conclusion II automatically follows from conclusion IV+(b)