I thought must introduced necessity

Hi Ella, You're correct that "must" introduces necessity. However we would want to change this diagramming a bit. Our sentence is "because of recent events Q must increase productivity 10% or it will go bankrupt" So if "must" is introducing a necessary condition, what is this a condition of? It's a condition of not going bankrupt. So we would diagram this as: Not go bankrupt -> increase P 10% (contrapositive: don't increase P 10% -> will go bankrupt). Our second sentence would be if P 10% possible -> 20% is attainable Therefore, our answer would be E. Because if a 20% increase is not attainable, then P 10% is not possible (contrapositive of diagram 2). And if we can't/don't increase P 10%, the company will go bankrupt.