What Action Did Facebook's COO,Sheryl Sandburg,take in Response to the Complaint

Multiple Choice

What action did Facebook's COO,Sheryl Sandburg,take in response to the complaint?

A) She issued a statement explaining the experiment and the concept of A/B testing.
B) She issued a half-hearted apology stating that the study was part of ongoing research companies do to test products and apologized for the lack of communication.
C) She issued an apology, urging Facebook and other companies to stop the unethical research on consumers.
D) She took no action.