Explanation:

- The phrase "worthy of" is commonly used to indicate that something deserves consideration, merit, or recognition.

- Option 1: "for" is used to indicate purpose or reason, and it doesn't fit the context here.

- Option 2: "about" is used to relate to a subject or topic but doesn't complete the phrase correctly.

- Option 3: "of" is the correct preposition in this context. It fits with "worthy" to form the phrase "worthy of consideration."

- Option 4: "on" indicates the surface of something or a subject but doesn't fit the phrase properly.