<qa>  What is the randomized, placebo-controlled trial design?Using a randomized, placebo-controlled trial design in subjects with vitamin D deficiency, the investigators propose to determine if vitamin D treatment improves glycemic control in vitamin D deficient subjects with T2DM. The investigators hypothesize that oral vitamin D treatment will improve glycemic control and ß-cell function in vitamin D deficient AA subjects with T2DM. The investigators further hypothesize that maintaining serum 25OHD concentrations above 20 ngml with oral supplementation of vitamin D will have additional glycemic control effects. 