The sentence "Jane plays the piano since she was eight" contains a grammatical error. The correct phrasing should be "Jane has played the piano since she was eight."
Explanation:
1. "Has played" is the best option to replace the underlined part because it indicates an action that started in the past and continues into the present, which is the case with Jane playing the piano since she was eight years old.
2. The use of "will plays" in option A is incorrect because it suggests a future action, which does not align with the past-to-present continuity of Jane playing the piano.
3. "Has been played" in option C is in the passive voice and does not convey the intended meaning of Jane actively playing the piano.
4. "Will have played" in option D indicates a future perfect action, which is not suitable for describing an ongoing activity that started in the past like Jane playing the piano.
In summary, the correct replacement for the underlined part is "has played."
