How many species can a genus include?

Nomenclature is governed by certain universal rules. Which one of the following is contrary to the rules of nomenclature?

Match Column-$I$ with Column-$II$ and choose the correct option.

Column-$I$	Column-$II$
$A$. Family	$I$. $Ipomoea$
$B$. Kingdom	$II$. Polymoniales
$C$. Order	$III$. $Solanum$
$D$. Species	$IV$. Plantae
$E$. Genus	$V$. Solanaceae

Identify the odd one out for wheat ($Triticum$ $aestivum$).

...... is the family of the cat.

Four statements are given below regarding the nomenclature of organisms. Which two statements are correct?
$(1)$ The first name denotes the species and the second denotes the genus.
$(2)$ $A$ species name used for one organism cannot be used for another organism.
$(3)$ Each word in a handwritten scientific name must be underlined.
$(4)$ It is mandatory to write the sub-species name after the species name for every organism.