Read the given statements and conclusions carefully. You have to take the given statements to be true even if they seem to be at variance from commonly known facts. You have to decide which conclusion(s) logically follow(s) from the given statements. 
Statements:
1. All coats are pants.
2. All pants are sneakers.
3. All sneakers are jackets.
Conclusions:
I. All coats are sneakers.
II. All pants are jackets.

Statements:

1. All coats are pants.
2. All pants are sneakers.
3. All sneakers are jackets.

​Conclusions:

I. All coats are sneakers. (True, all coats are pants and all pants are sneakers, that means all coats are sneakers).
II. All pants are jackets. (True, all pants are sneakers and all sneakers are jackets that means all pants are jackets).

So, ​Both I and II follows.

Thus, correct option is (b).