What is the purpose of the Row$\_$num argument in the following INDEX function?

$=$INDEX$($A$2$:B$5,$MATCH$($MAX$($B$2$:B$5),$B$2$:B$5,0),1)$

A$)$ To return the highest value in the range B$2$:B$5$

B$)$ To return the position of the highest value in the range B$2$:B$5$

C$)$ To return the column to the left of the highest values in the range B$2$:B$5$

D$)$ To return the row of the highest value in the range B$2$:B$5$