Replace the underlined verb in the given sentence with a suitable option:
Rich people think that only the poor are responsible for land pollute, while it is their own garbage cast around the poor localities.
a- Pollution
b- Pollutes
c- Polluting
d- Polluted

Hint: A compound noun refers to a noun that is formed by joining two or more words. For example- football, toothpaste, full moon, etc.

Complete answer:
As given in the hint, we need to choose an appropriate word to form a compound noun with ‘land’.
Let’s look at nouns-
A noun refers to a word that indicates the name of a person, place, thing, or animal. For example- dog, cat, book, etc.
In the given question- We can conclude that Rich people think that only the poor are responsible for land pollution, while it is their own garbage cast around the poor localities. Here, we have used ‘pollution’ because the statement indicates a condition, not an action. Hence, we needed to use an appropriate noun and form the concrete noun, ‘land pollution’.
Let’s examine the given options-
Option a- ‘Pollution’ is the correct option because it states a condition and does not denote an action. Hence, it is a noun.
Option b- ‘Pollutes’ is an incorrect option because it is the present tense form of the verb ‘pollute’.
Option c- ‘Polluting’ is an incorrect option because it is the continuous form of the verb ‘pollute’.
Option d- ‘Polluted’ is an incorrect option because it is the past tense form of the verb ‘pollute’. The correct answer is Option ‘a’.

Note:
Keep in mind, most nouns are formed by joining suitable suffix to adjectives or verbs. For example- Wisdom is a noun that is formed by joining the suffix ‘dom’ to the adjective ‘wise’.