EB-1 is the first employment-based preference category for obtaining a green card through employment.
EB-1A: Extraordinary Ability
For individuals with extraordinary ability. You may file on your own (self-petition), without an employer. The criteria are similar to O-1A, but the standard is higher.
EB-1B: Outstanding Professors and Researchers
For scholars and professors with international recognition. Requires a minimum of 3 years of experience and a job offer from a university or research institution.
EB-1C: Multinational Managers and Executives
For managers and executives of multinational companies. Requires at least 1 year of employment abroad with an affiliated company within the past 3 years.