columnar growth pattern

16. 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?
(A) A columnar juniper growing in an
atmosphere of intense heat and an
absence of carbon monoxide
(B) A normal juniper growing in an atmosphere
of intense heat and an absence of carbon
monoxide
(C) A columnar juniper growing in an
atmosphere of normal heat and a high
concentration of carbon monoxide
(D) A normal juniper growing in an atmosphere
of intense heat and a high concentration
of carbon monoxide
(E) A columnar juniper growing in an
atmosphere of intense heat and a high
concentration of carbon monoxide