Find odd one W.R.T plants having succulent system
A. Opuntia
B. Euphorbia
C. Citrus
D. Both 1 and 2

Hint: They are also known as succulents with their parts that are thickened and fleshy . they usually have the ability to in arid climates or soil conditions.

Complete answer:
Opuntia, are generally called as prickly pear which is a genus in the cactus family, Cactaceae. Prickly pears are also called tuna . The genus is named for the Ancient Greek city of Opus wherever, according to Theophrastus, which is an edible plant that grows and can be propagated by rooting its leaves. The mainly known cooking species is the Indian fig opuntia.
Euphorbia is a very large and diverse genus of flowering plants which are commonly called spurge. Euphorbia is at times used to collectively refer to all members of Euphorbiaceae. Some euphorbias are commercially broadly available. Some are usually cultivated as ornamentals or collected and highly valued for the visual appearance of their distinctive floral structures.

Citrus is a genus which are seen in the flowering trees and shrubs in the rue family Rutaceae. Plants in this genus mainly produce citrus fruits, consisting of important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus Citrus originates from South Asia, East Asia, Southeast Asia, Melanesia, and Australia.
Succulent plants can store water in their fleshy leaves and stems. Opuntia and Euphorbia have the ability to store water in their leaves and stem. while in the case of citrus it is not possible

Hence, the correct answer is option (C)

Note: Succulent plants convert the contaminants as plant food and thus purify the air. For the reason that they can release water and thus it enhances the humidity of the environment.