7. The United States, Japan, and France are classified as developed countries
because
A the people are healthy and educated
B they have a low GDP
C they have a high trade balance
D the people receive little health care

I assume that the answer A explains why they are developed countries and also the most obvious answer.

If people are healthy and educated in a country it is assumed that there is a vast amount of access to basic needs and services (suggesting why A is the answer).

Why the other answers aren't necessarily correct:

Low GDP can be bad for the economy ruling out Answer B

High Trade Balance as in a deficit or a surplus? Are they producing more than they buy or buying more than they produce? A surplus would indicate that the economy is good, but a deficit would be bad for the economy. Depending on this, Answer C may/may not be the answer.

People receiving little health care means that they may pass away as a result of little to no access to basic needs and services. Answer D would be the least correct answer out of the four answers.

are these the benchmarks questions?

the outcome of 1970 oil crisis in united states was that, they began to search ways on how to reduce oil.

in 1970 was a period when there were energy and oil crisis. those who were major centers for industrialization were forced to keep way from supplying of petroleum.

some of the result of this crisis was economic growth became stagnant because prices of oil surged.

due to the increased prices some countries like mexico and norway benefited.