Question

as janelle posted online, she appreciated the anonymity provided by her username. this means she...
enjoyed being unknown or unrecognizable.
frequently shared personal details about herself.
was easily recognizable to everyone.
felt exposed and open to others.

Explanation:

The word "anonymity" means the state of being anonymous, i.e., unknown or unrecognizable. So if Janelle appreciated the anonymity from her username, she enjoyed being unknown or unrecognizable. The other options ("frequently shared personal details", "was easily recognizable", "felt exposed") are opposite to the concept of anonymity.

Answer:

A. enjoyed being unknown or unrecognizable.