Answer and Step-by-step explanation: Marginal Benefit is the maximum a person is willing to pay for an additional good or service. It can be calculated as:

For each cup of coffee:
For the first cup, benefit is $8;
For the second:

marginal = 6
For the third:

marginal = 4
For the fourth:

marginal = 2
For the fifth:

marginal = 1
The cost of the coffe is $3, so comparing benefit and cost, Neal should consume 4 cups of cofee per day.