The correct option is A Informative
Adjectives are words that modify nouns or pronouns to make them more specific.
From the options given:
'informative' is an adjective which means 'providing useful information'. 'informing' is a verb which is 'the act of providing useful information'.
'informed' is also an adjective which means 'having knowledge of a subject.'
'informs' is a verb which means 'to give someone a fact or information'.
Between 'informative' and 'informed', the right adjective to use with a book which is a non-living thing is 'informative' and therefore the correct answer is option A).
'Informed' is generally used while referring to people and so it is incorrect.
Options B and D are incorrect because they are verbs and not adjectives.