since \(1975,\) total government expenditures as a percentage of GDP in the United States have a. fallen by half. b. remained fairly constant at about one-third. c. grown from one-fourth to one-half. d. grown from one-quarter to one-third.

First, we need to have a clear understanding of the terms involved. GDP (Gross Domestic Product) is the total monetary value of all the goods and services produced within a country over a specific period. The total government expenditures refer to the amount of money the government spends during a given year. In this exercise, we are interested in knowing how the percentage of total government expenditures to GDP has changed since 1975. Note that we are not given specific data values or a chart, so this question tests general knowledge about the economics and government spending history of the United States. If we had more historical data available, we could calculate the percentage for each year and then choose the correct option.

We have four options: a. Total government expenditures as a percentage of GDP have fallen by half since 1975. b. The percentage has remained fairly constant at about one-third since 1975. c. Total government expenditures as a percentage of GDP have grown from one-fourth to one-half since 1975. d. The percentage has grown from one-quarter to one-third since 1975. These options do not require any arithmetic calculations, as each option presents a statement about how the percentage has changed. We need to make a well-informed guess based on a general understanding of the changes in United States' government spending patterns over the past few decades.

From various sources of historical data, we can determine that option (b) is the most accurate description of the change in total government expenditures as a percentage of GDP in the United States since 1975. During this period, the percentage has remained relatively constant at about one-third of the GDP. Answer: (b) remained fairly constant at about one-third.