When is peak bone mass achieved among the following?

Peak bone mass is achieved in early adulthood after the cessation of skeletal growth. This set point is determined by a variety of factors, including polymorphisms in the receptors for vitamin D and LRP5/6, nutrition, physical activity, age, and hormonal status. Beginning in the fouh decade, however, resorption exceeds formation, so there is a steady decline in skeletal mass.Robbins Pathology 9e pg: 1183