Which statement is objective? Newton’s rules explain how gravity affects objects.
The history of black hole detection is very interesting.
The scientists who make discoveries are brilliant.
Albert Einstein is the most famous of all the scientists.

"Newton's rules explain how gravity affects objects"

Explanation:

Simple heuristic:

Descriptions of quality (interesting, famous, brilliant) are always subject to the context (person, time period, entity, etc).

Newton's rules of gravity are NOT subject to context, thus objective.