Three statements are given followed by three conclusions numbered I, II and III. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follow(s) from the statements.
Statements:
Some cups are glasses.
No glass is a stone.
All stones are metals.
Conclusions:
I. All cups can never be stones.
II. No cup is a metal.
III. All metals can never be glasses.