Step 1: Meaning of aftercare.
Aftercare refers to support provided to children who have completed institutional care and are transitioning into independent adulthood.
Step 2: Statutory age limit.
The Juvenile Justice (Care and Protection of Children) Act, 2015 provides that aftercare services may be extended to persons who have attained the age of 18 years and up to the age of 21 years.
Step 3: Objective of aftercare.
The purpose is to facilitate rehabilitation, social reintegration, education, and employment support during early adulthood.
Step 4: Conclusion.
Hence, the correct answer is (B) 18 to 21.