The correct option is D Foramen of Monro
The interventricular foramina (or foramina of Monro) are channels, that connect the paired lateral ventricles with the third ventricle at the midline of the brain. On the posterior side, both paracoel combine with each other and open into the cavity of diencephalon through an aperture known as foramen of Monro. The cavity of diencephalon is known as, third ventricle or diocoel.