Which of the Following Is True

Which of the following is true?

A) Generally, the lower the country's average income, the less administrative, scientific, and technical capacity it has to design and enforce standards.
B) National priorities do not change as income changes-countries of all income levels seem to share the same priorities and values.
C) Differences in income are always an obstacle to the harmonization of standards.
D) The adoption of a common set of rules usually narrows the market and raises prices.