Match the parts of the chromosome given in Column $I$ with their explanation in Column $II$:

Column $I$ (Chromosome)	Column $II$ (Explanation)
$1$. Centromere	$a$. Disc-shaped plate where spindle fibres get attached during cell division.
$2$. Secondary constriction	$b$. Long unbranched slender highly coiled $DNA$.
$3$. Kinetochore	$c$. Place where $2$ chromatids are joined together.
$4$. Chromatonema	$d$. Nucleolus gets organised at this place.

Choose the correct answer from the following options.

• A
  $1-c, 2-b, 3-d, 4-a$
• B
  $1-d, 2-c, 3-b, 4-a$
• C
  $1-c, 2-d, 3-a, 4-b$
• D
  $1-d, 2-a, 3-b, 4-c$