Assertion (A ) : The `19^(th)` electron in potassium atom eneters into 4s- orbital and not the 3d- orbital Reason (R : (n + l) rule is followed for determining the orbital of the lowest energy state. The correct choice is

Options

A. Both (A) and (R ) are true and (R ) is the correct explanation of (A )
B. both (A) and (R ) are true but (R ) is not the correct explanation of (A )
C. (A) is true but (R ) is not true
D. (A ) is not true but (R ) is true

Answer

A