Using ifelse conditional statements

So I have a large data set with and I would like to check a number of columns and rows with a key. There are 20 questions (columns) and 76 rows so that would be quite hectic to do by hand.

Q1  Q2  Q3  Q4  Q5  Q6  Q7  Q8  Q9  Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 Q19 Q20
        B   B   C   C   B   B   D   C   A   C   C   A   D   B   B   A   B   D
B   C   C   C   C   C   B   D   B   C   A   C   C   A   C   B   A   C   B   D
B   C   B   A   C   B   B   C   D   C   C   C   C   C   D   B   C   A   B   A
B   C   B   C   C   C   B   D   D   C   C   A   C   A   D   B   D   A   C   D
B   C   C   B   C   C   B   D   C   C   C   A   C   B   C   B   A   B   B   D
C   C   D   C   C   C   B   B   D   C   C   A   C   C   D   B   C   A   B   D
B   C   C   D   C   C   B   B   B   C   A   A   C   A   D   B   A   B   B   D
B   C   B   B   C   C   B   D   C   C   C   C   C   A   D   B   A   A   B   D
B   C   B   B   C   C   B   D   C   C   C   A   C   A   D   B   A   D   B   A
B   C   B   B   C   C   B   B   D   C   C   C   C   A   D   B   B   A   B   D
B   A   B   D   A   C   B   B   D   C   C   C   C   A   D   B   A   B   C   D
B   C   C   C   C   C   B   D   D   C   C   A   C   B   C   B   D   A   B   D
B   C   B   B   C   C   B   D   D   C   C   C   C   C   D   B   B   A   B   A
B   C   B   D   C   C   B   B   B   C   C   A   C   B   D   B   A   C   D   D
B   C   B   B   C   C   B   D   D   C   C   A   C   B   D   B   A   B   B   D
B   C   B   B   C   C   B   B   D   C   C   C   C   B   C   B   D   A   B   D
A   C   C   B   C   C   B   D   D   C   C   C   C   B   D   B   C   A   B   D
B   C   A   B   C   A   B   B   D   C   C   C   B   B   C   D   A   B   B   D

KEY=c('B', 'C', 'B', 'C', 'C', 'C', 'B', 'D', 'D', 'C', 'C', 'C', 'C', 'A', 'D', 'B', 'A', 'A', 'B', 'D');

I want to run a if and else statement, and maybe a for loop to assign a 1 to each column that has the correct letter corresponding to the key and 0 to ones that don't correctly correspond to the key. This is what I have so far, but I am unable to get it to go through the rows and columns correctly to assign the correct value.

 for(i in 1:nrow(scores)){
  if(scores[i,6:25] == KEY){
    scores[i,6] <- 1
  }
  else{
    scores[i, length(scores)] <- 0
  }
}

Any help would be appreciated!