Two 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 and definitely follow(s) from the statements.

Statements:

All donkeys are horses.

No cow is a horse.

Conclusions:

I. Some cows are donkeys

II. Some horses are donkeys.

III. No donkeys is a cow.