What structure is the $Crura$ $cerebri$ in the brain composed of?

Statement $I :-$ The cerebral medulla is referred to as the grey matter due to its greyish appearance.
Statement $II :-$ The neuron cell bodies are concentrated in cerebral medulla giving the colour.

Assertion : Midbrain and hindbrain (except cerebellum) form the brain stem.
Reason : Cerebellum has very convoluted surface in order to provide the additional space for many more neurons.

All spinal nerves are

Statement-$I$: Fibres of the tracts are covered with the myelin sheath,which constitute the outer part of the cerebral hemisphere.
Statement-$II$: The hypothalamus contains a number of centres which control body temperature,urge for eating and drinking. In the light of the above statements,choose the most appropriate answer from the options given below:

Brain stem is formed by .........