Discarded electronic items are categorized under
A. Industrial waste
B. Domestic waste
C. Hazardous waste
D. Electronic waste

Hint: Solid wastes are the wastes that are in the solid form. Discarded electronic items come under the category of solid wastes. Moreover, the electronic items that are discontinued after their use and are thrown away in the trash are known as the e-wastes.

Complete answer:
Solid wastes are the discarded or the left behind solid materials that are produced due to human activities. They basically refer to all the wastes that go out in the dumpsters and trash. The various kinds of solid wastes are Municipal wastes, Industrial wastes, Hospital wastes, Hazardous wastes, and Electronic wastes.
a. Municipal wastes - Municipal wastes are also known as Domestic waste. Municipal wastes are the solid wastes that are generated from homes, offices, schools, residential buildings, etc. They usually consist of paper, food wastes, plastics, metals, etc.
b. Industrial wastes - It is the solid waste that is generated from the Industries and Factories. It consists of the leftover items that are left after the processing of the various items. Usually, they consist of chemicals that are very harmful to the environment.
c. Hospital wastes - These wastes are those wastes that are generated from the hospitals. They consist of used syringes, drip bottles, bottles of medicines, wrappers of medicine, etc.
d. Hazardous wastes - They consist of elements that are unsafe for the environment. It usually consists of Radioactive wastes.
e. Electronic wastes - It is also known as the E-wastes. It consists of the discarded and left behind electronic items, the use of which has been discontinued so they are thrown in the trash.
Thus, the discarded electronic items are categorized under Electronic waste.
Hence, the correct answer is option (D).

Note: E-wastes or electronic wastes are a category of wastes that have emerged in the recent past decade. Disposal of e-waste is the need of the hour because they consist of a major proportion of the solid wastes. E-waste is being generated at a very fast rate and the developing nations are still struggling to find ways to deal with its safe disposal.