While estimating a reinforced cement structure, the omitted cover of concrete is assumed_______________?

A. At the end of reinforcing bar, not less than 25 mm or twice the diameter of the bar
B. In thin slabs, 12 mm minimum or diameter of the bar whichever is more
C. For reinforcing longitudinal bar in a beam 25 mm minimum or diameter of the largest bar which is more
D. All the above