Which of the Following Statements Is True

Multiple Choice

Which of the following statements is true?

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