Anyone can help advising me on what function to use if i wish to set up my excel?

E.g i entered in a excel box (Min Qualification = 'O' Level), it will show all 6 ('O' Level - Masters)

1, 'O' Level
2, 'A' Level
3, Diploma


4, Undergrad
5, Degree
6, Masters

I have created this link https://docs.google.com/spreadsheets...it?usp=sharing.

Thanks