Read the below statements.
I. All horses are donkeys.
II. All donkeys are monkeys.
III. No monkey is a tiger.
Which of the below conclusions logically follow(s) from the above statements?
(a) All horses are monkeys.
(b) Some donkeys are tigers.
(c) Some monkeys are horses.
(d) Some monkeys are donkeys

I. All horses are donkeys.
II. All donkeys are monkeys.
III. No monkey is a tiger.

Statement (I) says "All horses are donkeys," and statement (II) says "All donkeys are monkeys." Combining these two, it’s clear that all horses (being donkeys) must also be monkeys. Hence, this conclusion logically follows.
(b) Some donkeys are tigers.

Statement (III) clearly states that "No monkey is a tiger." Since all donkeys are monkeys (as per statement II), it is impossible for any donkey to be a tiger. Therefore, this conclusion does not follow.
(c) Some monkeys are horses.

From statement (II), we know that all donkeys are monkeys, and from statement (I), all horses are donkeys. Combining these two, we can deduce that some monkeys (specifically those who are donkeys) are horses. Thus, this conclusion logically follows.
(d) Some monkeys are donkeys​​

Statement (II) directly states that all donkeys are monkeys. This implies that some monkeys (those who are donkeys) are indeed donkeys. Hence, this conclusion logically follows.

Thus, the correct option is (d)  Conclusions a, c and d follow.