For the given compounds:
$I$: Pyridine
$II$: Pyrrole
$III$: $3$-Pyrroline
$IV$: Guanidine
The correct statement is:

Which is the best method for the preparation of $N$-methylethanamide?

When propionamide reacts with $Br_2$ in the presence of alkali the product is :

Which of the following compounds will have the highest $pK_b$ value?

Consider the following sequence of reactions. Total number of $sp^{3}$ hybridised carbon atoms in the major product $C$ formed is . . . . . . .

With respect to the following reaction,consider the given statements:
$C_6H_5NH_2 \xrightarrow{HNO_3, H_2SO_4, 288 \ K} \text{products}$
$(A)$ $o$-Nitroaniline and $p$-nitroaniline are the predominant products.
$(B)$ $p$-Nitroaniline and $m$-nitroaniline are the predominant products.
$(C)$ $HNO_3$ acts as an acid.
$(D)$ $H_2SO_4$ acts as an acid.