For an Rh incompatibility to occur during pregnancy, the mother must be

For an Rh incompatibility to occur during pregnancy,
  the mother must be
  a. positive and the father negative.
  b. negative and the father negative.
  c. negative and the fetus positive.
  d. negative and the father positive.
  e. positive and the fetus negative.

Question 2

In an Rh incompatability during pregnancy, the
  mother
  a. must be positive and her first and second fetuses
  positive.
  b. must be negative and her first and second fetuses
  positive.
  c. must be negative and her first and second fetuses
  negative.
  d. must be positive and her first and second fetuses
  negative.
  e. and the father must both be negative and the
  fetus positive.