In the United States proven oil reserves—the amount of oil considered

adkikani , You wrote:

If same volume of oil is available for extraction, and if no additional oil fields
are discovered, how could yearly consumption of domestically produced oil
. . . HAVE INCREASED without a simultaneous decrease in available oil levels [my words]?

Whoops. You are answering the wrong question. We do not need to explain the increase in consumption.

We need to explain this apparent paradox: increased consumption of oil should have decreased oil reserve levels. Oil reserve levels did not drop.

How can we consume more oil, but have the same amount of oil in reserve? That discrepancy needs to be explained.

I am not sure what went wrong.

Why is the "same volume of oil" available for extraction? There should be LESS.

Option D does not explain the disparity. Option D probably makes things worse.

1) A price drop does not explain the seeming contradiction between escalated consumption and oil reserves whose levels stayed the same although no new oil fields were discovered.

A lower price cannot explain how available reserve levels can be the same as 10 years ago. Price changes do not create more extractable oil.

2) Option D makes things worse.
If anything -- you are correct about this part -- decreased price equals increased consumption . . .

But a greater increase in consumption should FURTHER decrease reserve levels.
A price drop makes the discrepancy worse (harder to explain).

Increased consumption ... no new oil fields ... but proven oil reserve levels have not dropped? Have stayed the same?

Which answer explains this seeming paradox?

(E) Due to technological advances over the last decade, much oil previously considered unextractable is now considered extractable.

The same fields with the same oil have been altered; technology made the fields able to produce more oil.
That increased production compensated for, or offset, the increase in consumption.

This language is the key to the whole question: "proven oil reserves—the amount of oil considered extractable from known fields . . ."
When LSAC people write definitions that seem incidental or ancillary, pay very close attention to the language.
LSAC folks get specific with language for a reason.
In this case, the reason was to give us a BIG HINT about how to reconcile what seemed like contradictory events.
"Extractability" is the only part of the contradiction that has "give" (that has flexibility, that contains the potential for change).

Hope that helps.