Pith and cortex of the stem are parts of
A. Dermal tissue system – Epidermis
B. Vascular tissue system – Xylem and phloem
C. Ground tissue system – General cortex, endodermis, pericycle,medulla, medullary rays, conjunctive tissue, mesophyll
D. Epidermal tissue system – Epidermis
So, the correct option is ‘Ground tissue system’.