"Potato race, tulip race, onion race & daffodil race" refer to this nematode

Answer: Option B

"Potato race, tulip race, onion race & daffodil race" refer to Stem & bulb nematode.
Ditylenchus dipsaci is a plant pathogenic nematode that primarily infects onion and garlic. It is commonly known as the stem nematode, the stem and bulb eelworm, or onion bloat.
It is a migratory endoparasite that has a five-stage lifecycle and the ability to enter into a dormancy stage. D. dipsaci enters through stomata or plant wounds and creates galls or malformations in plant growth.