Which family preference category pertains to unmarried children of LPRs?

The family preference category that pertains to unmarried children of Lawful Permanent Residents (LPRs) is indeed F2B. This category is particularly designed for the adult unmarried children (21 years of age or older) of LPRs, allowing them to seek permanent residency in the United States.

In this context, the F2A category pertains to the spouses and children of LPRs, which does not apply to unmarried children. The F1 category is meant for the unmarried adult children of U.S. citizens, thus focusing on a different group altogether. Lastly, the F4 category is for siblings of U.S. citizens, which does not include any children of LPRs.

Understanding these terminologies and family categories is crucial, as they dictate the eligibility and processes related to family-based immigration in the U.S. The F2B category specifically addresses the needs of unmarried children of LPRs, making it the correct choice in this scenario.