In the Vascular Bundles of Most Dicot Stems,primary Phloem Differentiates

In the vascular bundles of most dicot stems,primary phloem differentiates toward the ________ of the stem,while primary xylem differentiates toward the ________ of the stem.

A) middle; outside
B) cork cambium; vascular cambium
C) outside; middle
D) shoot tip; roots
E) middle; middle