You find a chunk of petrified fossil wood and take it to a paleobotanist, who identifies it as palm (monocot) wood. What is the basis of this identification?

A) There are numerous tiny growth rings.
B) The vascular cambium appears active only between vascular bundles.
C) There is lots of heartwood and very little sapwood.
D) Only ground tissue and scattered vascular bundles occur in the specimen.