Down's syndrome is caused by the trisomy of which chromosome pair?

Given below are two statements :
Statement $I$ : Down's syndrome is caused by the absence of one of the $X$-chromosomes.
Statement $II$ : Turner's syndrome is caused by the presence of an additional copy of the chromosomes.
In the light of the above statements, choose the correct answer from the options given below :

Match the Column $I$ with Column $II$:

Column $I$	Column $II$
$(A)$ Autosomal trisomy	$(i)$ Turner's Syndrome
$(B)$ Allosomal trisomy	$(ii)$ Mendelian disorder
$(C)$ Allosomal Monosomy	$(iii)$ Klinefelter's Syndrome
$(D)$ Cystic fibrosis	$(iv)$ Down's Syndrome

An abnormal human baby with $XXX$ sex chromosomes was born due to

Match the following columns:

Column-$I$ (Disorder)	Column-$II$ (Ploidy)
$P$. Down's syndrome	$I$. Sex chromosomal trisomy
$Q$. Klinefelter's syndrome	$II$. Sex chromosomal monosomy
$R$. Turner's syndrome	$III$. Autosomal trisomy

In man,which of the following genotypes and phenotypes may be the correct result of aneuploidy in sex chromosomes?