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

Which of the following definitions best describes 'OBSOLETE filiform apparatus'?

A. OBSOLETE. A portion of plant tissue that covers the surface of the plant.
B. OBSOLETE. Area through which the pollen imports the nutrition during its development, at the time of pollen germination, the pollen tube emerges through it.
C. OBSOLETE. A complex of cell wall invaginations in a synergid cell similar to those in transfer cells.
D. OBSOLETE. The stage at which the root hairs are fully elongated.

Answer: OBSOLETE. A complex of cell wall invaginations in a synergid cell similar to those in transfer cells.