Institution: Bank Asia Ltd Exam: Bank Asia Ltd - Management Trainee Officer - 22.05.2015 ||
Topic: English literature, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

The correct answer to the fill-in-the-blank question is "Why, to, of," which fits grammatically and semantically with the structure of the sentence.

Starting with "Why," it introduces a question or an inquiry about the reason or cause behind the difficulty mentioned. This aligns well with the context of the sentence, which seeks to understand the challenges associated with waste disposal.

Next, "to" serves as the appropriate preposition that indicates the action of disposing. In English, we typically say "to dispose of something," revealing the intention or action toward managing waste. The use of "to" here indicates the purpose or goal related to the difficulty being discussed.

Finally, "of" is the correct preposition to follow "dispose" in this context. The phrase "dispose of waste" is a standard expression in English that indicates the act of getting rid of waste materials.

In summary, the combination of "Why, to, of" accurately captures the inquiry about the challenges in the process of waste disposal, making it the most suitable choice among the options provided.