If you sale all seven of them you might come across an isle or two, but the one with the treasure is in just a single what?\nOptions:\n- sea\n- river\n- ocean\n- body of water\n- auditorium
Stream of thoughts:
sea
Isle is an island or peninsula, especially a small one.

If you sail all seven of them you might come across an isle or two, but the one with the treasure is in just a single sea.

.

The answer is sea