An abnormal male child is born to normal parents. This child shows a short neck,stubby hands,slanting eyes,a permanently open mouth with a projecting upper lip,and short stature. This abnormality can be attributed to:

• A
  An extra $Y$ chromosome
• B
  An extra $X$ chromosome
• C
  An extra chromosome in the $21^{st}$ pair of autosomes
• D
  Absence of $X$ chromosome leading to a total of $45$ chromosomes instead of the normal $46$