The statement that is not correct for periodic classification of elements is.

A. The properties of elements are the periodic functions of their atomic numbers

B. Nonmetallic elements are less in number than metallic elements.

C. For transition elements, the 3d-orbitals are filled with electrons after 3p-orbitals and before 4s-orbitals.

D. The first ionisation enthalpies of elements generally increases with an increase in atomic number as we go along a period.