hello, I am trying to understand how the Q is solved. the only thing that I dont understand is how I find out the Marginal benefit. I will post a picture of the solution and here is the Q:

Sommer Inc. is trying to determine how much to spend on safety equipment for its planet. the first colum in teh table gives values for possible expenditures the second colum gives the expected # of worker injures. the third colum gives the expected severity per injury( cost to sommer per injury) associated with each expenditure level. How much should Sommer spend on safety if it's trying to maximaize firm value? ignore the time value of money.