The Pareto Principle:

Question $20$ options:

$80\%$ of the problems come from $20\%$ of the operation $(80-20$ rule$)$

$70\%$ of the problems come from $30\%$ of the operation $(70-30$ rule$)$

$90\%$ of the problems come from $10\%$ of the operation $(90-10$ rule$)$

None of the choices.

$99\%$ of the problems come from the $1\%$ of the operation $($the $1\%$ rule$)$