Which of the following is correct set of 4 quantum numbers of 19^...

The atomic number of Chromium is $24$.

According to the Aufbau principle, the order of filling of electrons is $1s, 2s, 2p, 3s, 3p, 4s, 3d$.

The electronic configuration of the first $18$ electrons is $1s^2 2s^2 2p^6 3s^2 3p^6$.

The $19^{th}$ electron enters the $4s$ orbital.

For the $4s$ orbital, the quantum numbers are:
Principal quantum number, $n = 4$
Azimuthal quantum number, $l = 0$
Magnetic quantum number, $m = 0$
Spin quantum number, $s = +\dfrac{1}{2}$ or $-\dfrac{1}{2}$

This matches the set given in the fourth option.

Answer: $n = 4, l = 0, m = 0, s = +\dfrac{1}{2}$