. Many things that society values, such as good health, high-quality education, enjoyable recreation opportunities, and desirable moral attributes of the population, are not measured as part of GDP. It follows that

a. GDP is not a useful measure of society's welfare.
b. GDP is still a useful measure of society's welfare because providing these other attributes is the responsibility of government.
c. GDP is still a useful measure of society's welfare because it measures a nation's ability to purchase the inputs that can be used to help produce the things that contribute to welfare.
d. GDP is still the best measure of society's welfare because these other values cannot actually be measured.

C. GDP is still a useful measure of society's welfare because it measures a nation's ability to purchase the inputs that can be used to help produce the things that contribute to welfare

Explanation:

It is useful because it allows everyone to judge a nations wealth based on a number, instead of looking at every aspect of the nation, they are able to see exactly how well the nation is doing.

Many investors or market analysts are able to predict the growth or decline of a nation by using this, as it can also be tracked throughout time, and compared to other nations.