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

Which of the following classes is one valid superclass of 'SE.00 stem elongation begins stage'?

A. 2.02 main shoot and axillary shoots visible at two nodes stage
B. stem elongation stage
C. B enlarged microsporocyte stage
D. 4 root elongation stage

Answer: stem elongation stage