Final answer:
Beyoncé said the statement about her alter ego, Sasha Fierce, indicating she had moved on from that persona.
Thus, the correct option is d.
Step-by-step explanation:
The statement "Sasha Fierce is dead. I killed her." was said by Beyoncé. Sasha Fierce was an alter ego created by Beyoncé to represent her on-stage and more aggressive performance style. This statement signifies Beyoncé's decision to move past that stage persona and integrate it into her whole self, rather than seeing it as a separate character.
Therefore, the correct option is d) Beyoncé