How many of the following statements are correct about niche?
$i$. It denotes the functional role played by an organism.
$ii$. It deals with the flow of energy from one organism to another.
$iii$. As soon as a niche is left vacant,other organisms fill that position.
$iv$. The same niche is shared by two or more species.
$v$. Organisms living in the same habitat differ in their niches.

• A
  $i, ii, iii$ and $iv$ only
• B
  $i, ii, iii$ and $v$ only
• C
  $i, ii, iii$ only
• D
  $iii, iv, v$ only