Undifferentiated ground tissue is present in stem of
A.Sunflower – Ground tissue is differentiated into hypodermis, general cortex and endodermis, pericycle, medulla and medullary rays.
B.Pisum - Ground tissue is differentiated into hypodermis, general cortex and endodermis, pericycle, medulla and medullary rays.
C.Maize – Ground tissue is undifferentiated.
D.Cucurbita - Ground tissue is differentiated into hypodermis, general cortex and endodermis, pericycle, medulla and medullary rays.
So, the correct option is ‘Maize’.