Question: Which arithmetic expression will give the most precise answer?

1. `var=$( expr 10 / 8 )`
2. `(( var= 10 /8 ))`
3. `var=$(( 10 / 8 ))`
4. `var=$(echo 'scale=2; 10 / 8' | bc)`

Answer: The correct answer of the above question is Option D:`var=$(echo 'scale=2; 10 / 8' | bc)`