Sentence Correction (SC) | Re: The Organization of Petroleum Exporting Countries (OPEC) had long been

1. usage of ", including X, Y and Z"

It indicates something includes X, Y, and X but not limited to. It includes other stuff too.

so using ", which includes.." changes the meaning. Now it means the "non-opec nations" only include these three countries i.e. Norway, Mexico, and Russia.

In option B and D, ",which includes..." here "which" refers to "non-opec nations" ... which is Plural. So break S-V agreement.

B and D can be
...

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