Answer :
Answer: Option (B) a decrease in a product's price raises MU per dollar and makes consumers wish to purchase more units is correct.
Explanation:
If the price of a commodity decreases, as a result purchasing power of a consumer increases as well as raises the MU per dollar. This is one of the reasons why the AD curve slopes downward.
Suppose there is a fall in the price of a commodity, this will increase the demand for that commodity as well as the purchasing power of the consumer.
Because with a lower price of the commodity, individuals can buy more quantity of goods with the same level of income as well as its marginal utility from an extra unit also increases.