$\begin{array}{1 1} (a)\; \text{Sperm, testes, sperm duct, *****} \\ (b)\; \text{Menstruation, egg, oviduct, uterus} \\ (c)\; \text{Sperm, oviduct, egg, uterus} \\ (d)\; \text{Ovulation, egg, oviduct, uterus} \end{array}$
