The number of s-electrons present in an ion with 55 protons in its unipositive state is

The magnetic moment of a transition metal compound has been calculated to be 3.87 B.M. The metal ion is

It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power "n" i.e. $${v^n}$$ of X-rays emitted is plotted against atomic number "Z", following graph is obtained.

The value of 'n' is :

Given below are the quantum numbers for 4 electrons.

A. $$\mathrm{n}=3,l=2, \mathrm{~m}_{1}=1, \mathrm{~m}_{\mathrm{s}}=+1 / 2$$

B. $$\mathrm{n}=4,l=1, \mathrm{~m}_{1}=0, \mathrm{~m}_{\mathrm{s}}=+1 / 2$$

C. $$\mathrm{n}=4,l=2, \mathrm{~m}_{1}=-2, \mathrm{~m}_{\mathrm{s}}=-1 / 2$$

D. $$\mathrm{n}=3,l=1, \mathrm{~m}_{1}=-1, \mathrm{~m}_{\mathrm{s}}=+1 / 2$$

The correct order of increasing energy is