Do You Know about Letters 'A','B','C','D'

Letters 'A', 'B', 'C' and 'D' do not appear anywhere in the spellings of 1 to 99.
(Letter 'D' comes for the first time in Hundred).

Letters 'A', 'B' and 'C' do not appear anywhere in the spellings of 1 to 999.
(Letter 'A' comes for the first time in Thousand).

Letters 'B' and 'C' do not appear anywhere in the spellings of 1 to 999,999,999.
(Letter 'B' comes for the first time in Billion).

And

Letter 'C' does not appear anywhere in in the spellings of entire English Counting.