Vector of citrus greening is

Answer: Option A

The vector of citrus greening is Psyllid.
The natural vector of African citrus greening and D. citri is the natural vector of Asian citrus greening, either psyllid vector can transmit both greening agents under experimental conditions.
The Asian citrus psyllid, is the most important pest of citrus worldwide because it serves as a vector of "Candidatus Liberibacter" species (Alphaproteobacteria) that cause huanglongbing (citrus greening disease).