Latex vessels is characteristic of
Latex vessels are a result of the fusion of many cells. They grow more or less as parallel ducts, and in the mature portion of the plant, they anastomose with one another with the fusion of their branches, forming a network. Latex vessels are found in the family Papaveraceae (Poppy).
Opuntia is commonly called as prickly pear, is a genus in the cactus family, Cactaceae. Prickly pears.
C. Nerium is a shrub or small tree in the dogbane family Apocynaceae, toxic in all its parts.
So, the correct answer is A.