From among the situations given below, choose the one that prevents both autogamy and geitonogamy.
a. A monoecious plant bearing unisexual flowers
b. A dioecious plant bearing only male or female flowers
c. Monoecious plant with bisexual flowers
d. Dioecious plant with bisexual flowers
The answer is the option (a) Monoecious plant bearing unisexual flowers
Autogamy can happen in case of bisexual flowers. Geitonogamy can happen in case of dioecious plants bearing only male or female flowers. Hence, option (a) is correct.