They are known as vitamins A, the B group,C,D,E and K.
VOA: special.2009.04.21
It was a short way of writing a different spelling of the words all correct. Some foreign-born people wrote all correct as o-l-l k-o-r-r-e-c-t, and used the letters O.K.
VOA: special.2010.02.28
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