Question

Statements: some marbles are pens. Some pens are dogs. Some dogs are doors. Conclusions: (i) some doors are pens. (ii) some dogs are marbles. (iii) some marbles are doors.

Answer 1

Only #3 is only sometimes correct

For the other ones it is always correct

Answer 2

I think that the correct answer is
(iii)some marbles are doors.