Osteomalacia and rickets

A 2-year-old African American boy is brought to the clinic by his mother with bone pain and difficulty walking for the past month. Physical examination shows a soft skull with frontal bossing, bumps along the costochondral junction, short stature, and bowing of the legs. X-rays show epiphyseal widening and metaphyseal cupping. His mother says that the child has been exclusively breastfed. Which of the following best describes the most likely serum laboratory values?