Select the group of $CORRECT$ statements.
$I$. If phenotype of offsprings shows only the dominant trait then the parent plants are heterozygous.
$II$. $A$ true breeding line shows stable trait inheritance and expression for several generations.
$III$. In mendelian experiment material,contrasting characters can be easily recognized.
$IV$. When a single gene controls two (or more) different traits,it is called polygene.
$V$. When interactions occurs between the alleles of different genes present on the same or different chromosome it is called intragenic interaction.

• A
  $III$ and $V$ only
• B
  $II$ and $III$ only
• C
  $III$ and $IV$ only
• D
  $I$ and $V$ only