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:
No river is a sea.
Some rivers are lakes.
All rivers are ponds.

Conclusions:
I. Some lakes are seas.
II. Some ponds are seas.
III. Some lakes are ponds.