Which one of the following can be explained on the basis of Mendel's Law of Dominance?
$A$. Out of one pair of factors one is dominant and the other is recessive.
$B$. Alleles do not show any expression and both the characters appear as such in $F_2$ generation.
$C$. Factors occur in pairs in normal diploid plants.
$D$. The discrete unit controlling a particular character is called factor.
$E$. The expression of only one of the parental characters is found in a monohybrid cross.
Choose the correct answer from the options given below:

• A
  $A, C, D$ and $E$ only
• B
  $B, C$ and $D$ only
• C
  $A, B, C, D$ and $E$
• D
  $A, B$ and $C$ only