Which of the following commands will reduce all consecutive spaces down to a single space?
A . tr ‘s’ ‘ ‘ < a.txt > b.txt
B . tr -c ‘ ‘ < a.txt > b.txt
C . tr -d ”< a.txt > b.txt
D . tr -r ‘ ‘ ‘
‘ < a.txt > b.txt
E . tr -s ‘ ‘ < a.txt > b.txt
Answer: E