Task: Class Relation Understanding (ontology: Food_Agriculture/PlantOntology)

Which of the following classes is one valid superclass of 'stereid'?

A. 2.02 main shoot and axillary shoots visible at two nodes stage
B. IE.03 3/4 of inflorescence emerged from flag leaf sheath stage
C. 4 root elongation stage
D. ground tissue cell

Answer: ground tissue cell