In Phlox, the vascular cylinder is continuous and consists of a single layered pericycle, a complete ring of phloem, a complete ring of cambium and a complete cylinder of xylem with a pith in the centre. This arrangement of the vascular tissue is called

A. Ectophloic siphonostele

B. Endophloic siphonostele

C. Amphiphloic siphonostele

D. Mixed protostele

Answer: Option A