Final answer:
If a child has a BMI above the 85th percentile at a young age, they are more likely to be overweight at age 12.
Step-by-step explanation:
Obesity in children is determined by comparing the child's BMI to reference values. If a child has a BMI above the 85th percentile at 24, 36, or 54 months, they are considered to have a BMI higher than that of 85% of same-aged children in the reference sample. This indicates that they are more likely to be overweight at age 12 compared to a child with a normal BMI. Therefore, the correct answer is a) 2.