$\backslash$table$[[50D,$Barely pass$],[55D+,$Pass$],[60C,$Credit$],[65C+,$Good Credit$],[70B,$Good$],[75B+,$Very Good$],[80A,$Excellent$]]$

Use a vlookup function to calculate the letter grades from $C4$ to $C18,$ based on the marks earned in $B4$ down to $B18.$ Also use a vlookup function to calculate the Grade Description from D$4$ to D$18,$ based on the marks earned in B$4$ down to B$18.$