Which of the Following Statements Is True

Multiple Choice

Which of the following statements is true?

A) We can determine the exact location of an electron if we know its energy.
B) Ni has 2 unpaired electrons in its 3d orbitals.
C) An electron in a 2s orbital can have the same n, l, and m_l quantum numbers as an electron in a 3s orbital.
D) Only three quantum numbers are needed to uniquely describe an electron.
E) In the building up of atoms, electrons occupy the 4f orbitals before the 6s orbitals.