Below is a $2$D array:

$24751$

$69345$

$25849$

a$.$ What number is at index $[1,3]?$

The number at $[1,3]$ is $4.$

b$.$ If you used an Array Subset function on the above array, and assigned the following input values $($in order$)$:

index: $2$

length: $3$

index: $3$

length: $2$

What value$($s$)$ would be returned? Would it be a $1$D or $2$D array?