Identify the homoleptic complex(es) that is/are low spin.

(A) $\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]^{2-}$

(B) $\left[\mathrm{CoF}_6\right]^{3-}$

(C) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$

(D) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$

(E) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$

Choose the correct answer from the options given below :

The maximum number of RBr producing 2-methylbutane by above sequence of reactions is __________ . (Consider the structural isomers only)

The alkane from below having two secondary hydrogens is :

Residue (A) +HCl (dil) $\rightarrow$ Compound (B)

Structure of residue (A) and compound (B) formed respectively is :