Consider the following statements:
1. Some claim to have seen UFOs (Unidentified Flying Objects).
2. Life on other heavenly bodies is considered to be a possibility.
3. Voyage to space is now an established fact.
From the above statements, it may be concluded that
(a) UFOs are heavenly bodies
(b) UFOs are sent from other heavenly bodies
(c) Some living species in other heavenly bodies are more intelligent than man
(d) Nothing definite can be said about the UFOs
