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

Which of the following definitions best describes 'BBCH 63 evaluation'?

A. Assessment of the date when at least 50% of the buds have the tips of the first leaves that extend beyond the tip of the scales, which may still be present. The leaves begin to individualize. In pines, the needles begin to pierce the sheath. In other conifers the first buds show individualized needles in closed brush.
B. Assessment of the date when 90% of the crown fruits are mature (has changed color or is dried and dehiscent or has fallen)
C. Assessment of the date when 30% of flowers are sexually mature. For flowers with petals: petals are spread out and stamens release pollen. For male flowers in catkins: stamens are visible and release pollen. Other male flowers: stamens are visible and release pollen.
D. Assessment of the date when leaves are coming out of their bud. For broadleaves: the first leaves are spread on about 20% of the crown. For pines: 20% of very elongated buds with first needles coming out or out of the sheath but still tight, as stuck between them. For other conifers: 20% of buds with open-brushed needles.

Answer: Assessment of the date when 30% of flowers are sexually mature. For flowers with petals: petals are spread out and stamens release pollen. For male flowers in catkins: stamens are visible and release pollen. Other male flowers: stamens are visible and release pollen.