James and Charlotte Were Thrilled to Find Out They Were

James and Charlotte were thrilled to find out they were going to have a baby. The first pregnancy had gone so well, they expected no problems with this one. If this is true, what is the Rh combination that James and Charlotte must have?

A) James must be Rh^- and Charlotte must be Rh^-.
B) James must be Rh^- and Charlotte must be Rh⁺.
C) James must be Rh⁺ and Charlotte must be Rh⁺.
D) Any of these