Valid ways of saying a fraction using (saying) cardinal number as its denominator
I think B: twenty three hundredths and D: twenty three one hundredths are the only ones that you could say and sound correct. There is the possibility of being misunderstood but people are rather used to that and look for clarification. One would only use hundredth as a singular to say One hundredth as in "one and only one hundredth" since the One is itself singular. A hundredth or one or two one-hundredths is enough by itself.