Conceptually, Why Would Openness to Experience Be Associated with a Pattern

Conceptually, why would openness to experience be associated with a pattern of brain activity rather than a specific brain region, as neuroticism or extraversion are?

A) Openness to experience involves a great deal of creativity, but there is no evidence that creativity has any link to brain activity.
B) The other Big Five traits are poorly defined, so tagging a specific brain region to a specific trait is a way of simplifying our understanding of these personality dimensions.
C) In contrast to neuroticism, which has been linked to a single area of the brain, the amygdala, openness to experience is a more diffuse concept enlisting many brain regions.
D) Only one facet of openness to experience-modesty-has been linked reliably to any kind of brain activity; there simply isn't a lot of evidence for this Big Five trait.