Using Records Taken by Henry David Thoreau in the 1840s

Using records taken by Henry David Thoreau in the 1840s, scientists have documented what pattern of change in flowering plants around Boston, Massachusetts?

A) As temperatures have warmed, flowering occurs earlier in many species.
B) As temperatures have warmed, flowering occurs later in many species.
C) As temperatures have become more variable, flowering occurs earlier in many species.
D) As temperatures have become more variable, flowering occurs later in many species.
E) As extreme weather events have become more common, flowering occurs earlier in many species.