Mrs. B One had two kids : Master C One and Miss D One
P.S There are two valid answers.
P.P.S The first three who answer correctly will find a personalised email in their mail boxes from me, containing a never heard before ( I think) LJ (lame joke)
P.P.P.S Answers to be declared tomorrow same time. Since no copying will be allowed, all comments will be published at the same time with the answer. What? Its exam time all around buddies 😈 😈
Edited to add:
First answer is Mr.One
Second answer is though technically the husband of Mrs. B One is Mr. One, you cannot be sure he is the father of the kids 😈
DI answered the riddle perfectly, actually to the T, damn good D 🙂