GMAT Critical Reasoning (CR) | Re: American "heirloom" tomatoes, once common varieties of the fruit that

clearly, there is a cause-effect relationship between these two statements.
first one is definitely not an objection nor a position.
it's a hypothetical statement. In case X, then Y.
in the end, we have a conclusion that is totally different from X and Y.
so we have an opposition to the main conclusion.
just based on this analysis, we can eliminate all but D.

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