The number of sori on the sporophyll in Nephrolepis are
The number of sori on the sporophyll in Nephrolepis is 50. Sori occur on the sporophyte generation, the sporangia within producing haploid meiospores. As the sporangia mature, the indusium shrivels so that spore release is unimpeded. The sporangia then burst and release the spores.
Therefore, the correct answer is option D.