What is the name of Data's evil twin brother?

Data’s evil twin brother is Lore. Lore is an android built by the cyberneticist and scientist Dr. Noonien Soong before Soong created Data. Although Lore and Data are physically similar, Lore develops a dangerous sense of superiority and lacks the ethical restraint that defines his younger brother.

Lore first appears in the first-season episode “Datalore,” where the Enterprise crew discovers him on Omicron Theta, the colony where Data was originally constructed. Lore had been dismantled and hidden after the colonists became suspicious of his behavior. He eventually betrays the crew and escapes, establishing him as one of Data’s most personal adversaries.

Lore returns in “Brothers” and “Descent.” In the latter story, he manipulates a group of liberated Borg and uses Data’s emotion chip to trigger negative emotions in him. The other options refer to different androids, technologies, or people: B-4 is another Soong android, while Noonien Soong is Data’s creator, not his brother.