Answer:
b
Step-by-step explanation:
Marginal utility is the additional utility derived from consuming one more unit of a good
the consumption decision is to consume more units of a good that gives the higher utility per good.
Marginal utility per unit of good = marginal utility / price of the good
haircut = 2000 / 40 = 50
Nails = 1000 /25 = 40
the utility per unit for haircut is greater for haircut than nails, so he would choose haircut
When marginal utility is positive, it means that increasing consumption by one unit increases total utility
When marginal utility is negative, it means that increasing consumption by one unit decreases total utility
When marginal utility is zero, total utility has reached its maximum and no more units of goods would be consumed