B. The feathers (noun) were beautiful (adjective), long (adjective), and dark (adjective).
In sentence A, Taha (noun) kept (verb) his feather-gathering (verb) a secret. So although the first sentence tells you about what Taha does, it does not describe him as a noun as the second sentence does by detailing the feather through adjectives.
The key questions to ask when refining and polishing your thesis statement are: does the thesis question address the assignment? Can you clarify any vagueness in phrasing or assertions? Are there any alternatives to your thesis statement?