The cause of the peculiar columnar growth pattern displayed by juniper

The cause of the peculiar columnar growth pattern displayed by junipers growing near burning underground veins of lignite coal has never been convincingly explained. Until recently, the accepted theory posited that the abundance of carbon monoxide in the local atmosphere caused the columnar growth. However, a new theory holds that the cause is the persistent heat present near these underground fires which, while not intense enough to inflame the trees, can nonetheless change their normal growth pattern.

The existence of which of the following would provide the strongest support for the new theory?

junipers has peculiar growth pattern near:
(1) abundance of carbon monoxide
(2) persistent heat present
we have to find a situation, in which the junipers present a columnar growth pattern when there is present (2)

A. A columnar juniper growing in an atmosphere of intense heat and an absence of carbon monoxide.
columnar refers to grow pattern, not to the junipers
B. A normal juniper growing in an atmosphere of intense heat and an absence of carbon monoxide.
this states that junipers has peculiar columnar growth pattern near (2)
C. A columnar juniper growing in an atmosphere of normal heat and a high concentration of carbon monoxide.
same as A.
D. A normal juniper growing in an atmosphere of intense heat and a high concentration of carbon monoxide.
Not exclude (1)
E. A columnar juniper growing in an atmosphere of intense heat and a high concentration of carbon monoxide.
Errors of A + D

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