The hybrid atomic orbitals are formed by the combination of the valence orbitals on an atom. The hybrid orbitals formed have different energy and shape compared to the atomic orbitals that combine to form the hybrid orbitals. Hybrid orbitals help in explaining the shapes of the molecules and other bonding properties.
Therefore the correct answer will be,
b. A mixture of the valence orbitals in an atom
e. There are as many hybrid orbitals as there are valence orbitals that mix together.
f. Hybrid orbitals have a different shape and different energy than the atomic orbitals of which they are made