R skills $(4$ points$)$ Group the variable marital status $($marital status$)$ into the following categories in

the NHANES dataset:

Never married $($Code: $4)$

Married$/$Living with partner $($Code: $0,5)$

Other $($divorced$/$separated$/$widowed$)($Code:

$2,3,1)$

Missing $($missing$,$ refused, don't know$)$

$($Code: missing, $6,7)$