After examining the blood groups of husband and wife, the doctor advised them not to have more than one child. The blood groups of the couple are likely to be
| 1. | Male Rh- and Female Rh+ | 2. | Male Rh+ and Female Rh+ |
| 3. | Male Rh+ and Female Rh- | 4. | Male Rh- and Female Rh- |