Comparing text values to target text row

Question

I'm trying to make my Google Sheets (that is populated with textual responses from Google Forms) to color the background of the "wrong" cells red. I have the correct answer for each column at the very top in row 1. These are all alphabetical text, not numerical answers.

How would I go about in having it compare the values of each column to the top row?

IF the value is NOT EQUAL to the top of the column, that cell is colored. so the "wrong" responses in the below example will be colored, as it isn't the same text as the top row.

____A___B___C___D__
1 ans1 ans2 ans3 ans4
2 wrong ans2 ans3 wrong
3 ans1 ans2 wrong ans4

LINK to the spreadsheet

Answer 1

Format, conditional formatting, custom formula is:

=AND(LEN(A2),A2<>A$1)

and apply that to range A2:x, where x is the lowest and right-most cell of the range you want to apply this to.