Trying to put the most common number for a survey but not working

I need help with excel. For my homework Im putting in data for a survey. Im just trying to get like what is the most common number / letter for the questions. For example collom b for (scale of 1-7 is the name) the common number be 7 and for (binary scale that the name) it would be "Y" Of course I can just see that but I need to put the the ??code??function?? thing but Im not sure on how to do that with letters and when I tried with numbers it gave me 6 when the most common number in collum B is 7. This was the code I used =AVERAGE(B12:B17)

[Scale of 1–7][7__________]

[_____________][6__________]

[_____________][7__________]

[_____________][7__________]

[Common___][6__________] <wrong answer

[Binary Scale][y__________]

[_____________][y__________]

[_____________][a__________]

[_____________][y__________]

[Common___][ #DIV/0!__]