Choose the correct adjective from the options given.
This book is very ________________.
a. Informative
b. Informing
c. Informed
d. Informs

Hint: Some adjectives take the suffix ‘ive’. For e.g. - festive, descriptive, prescriptive, etc.

Complete answer:

Adjectives are also known as describing words. Adjectives tell us more about the noun by describing their qualities. Adjectives can be of two types- Qualitative and Quantitative. If an adjective describes the quality of a noun, it is qualitative. If an adjective describes a noun in terms of number, it is quantitative.
Let us look at an example - The garden was very beautiful. Here, beautiful is the adjective as it describes the garden.
Now, let us look at the four options and see the function of ‘inform’ in that option.
In option ‘a’, informative can tell us more about any given noun. Thus, it is an adjective.
In option ‘b’ informing denotes a Present Participle or the ‘ing’ form of a verb. The Present Participle is used in the Continuous and Perfect Continuous Tense types. Therefore, it is a verb.
In option ‘c’, informed denotes a Past Participle. Past participles are used in the Past Perfect Tense and the Present Perfect Tense. They are generally paired with auxiliary verbs.
In option ‘d’, informs refers to the infinitive ‘to inform conjugated in the Simple Present Tense. It stands for action. Therefore, it is a verb.
From the above explanation, we can conclude that option ‘a’ informative is the correct answer as it is an adjective and fits the context of the question.

Note: Understanding the different forms of the word as different parts of speech is the key to solving this question.