Which of the following substances is not paramagnetic?

Which of the following general configurations of the outermost shell represents the chromium element [$Cr$'s atomic number $= 24$]?

Which of the following rules must be followed to form an alloy?

Which pair of elements from the following has half-filled $d$-orbitals in their observed electronic configuration?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$. Assertion $(A)$: In aqueous solutions $Cr^{2+}$ is reducing while $Mn^{3+}$ is oxidising in nature.
Reason $(R)$: Extra stability to half-filled electronic configuration is observed than incompletely filled electronic configuration.
In the light of the above statement,choose the most appropriate answer from the options given below:

The ions of $d$-block elements are paramagnetic because.....