Critical Reasoning (CR) | The cause of the peculiar columnar growth pattern displayed by juniper

IMO the answer is D.

We need to "strengthen" the new theory as well as "weaken" the previous theory -
1 - persistent( and not intense) heat is the cause of change in growth pattern
2 - carbon monoxide abundance is the cause


A. A columnar juniper growing in an atmosphere of intense heat and an absence of carbon monoxide.
- weakens (1).
B. A normal juniper growing in an atmosphere of intense heat and an absence of carbon monoxide.
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