Book is a non-living noun, and for referring to a non-living noun we use pronoun 'which'.

Pronoun 'which' is used for non-living things, and pronoun 'what' is used for abstract nouns. For living nouns (in subjective form) we use pronoun 'who'.

Kind of books refer to nature of the books. Nature of something is an abstract noun, and for referring to abstract nouns we use pronoun 'what'.

The matter here is abstract, and for referring to abstract nouns we use pronoun 'what'.

Here the reciever of award is the subject, and for living subjects we use pronoun 'who'.

Here the top scorer of the innings is the subject (i.e. doer of the verb). So, pronoun 'who' should be used.

Whenever we start a sentence in reference to more than one person, we use pronoun 'which' (in fact of being the case of living nouns).

Whenever we ask for somebody's preference between/among some articles, we use pronoun 'what'.

One's opinion is abstract and for reffering to abstract nouns we use 'what' as pronoun.

For the living nouns (in objective cases) we use pronoun 'whom'.

The sentence does not clarify the thing they fought for, so we should use the pronoun 'what'. 'Who' is used for subject and 'whom' represents possession. We use 'which' for things. So, these options are not correct.

For non-living nouns we use pronoun 'which'. Books are non-living things.

For living nouns (in subjective cases) we use 'who'. As the visiter is the doer of the action, thus 'who'.

Predicting the future is an action, and doer of the action takes pronoun 'who'.

The thing/action that makes him angry is unclear here, and for referring to abstract nouns we use pronoun 'what'.

To refer to a person we use pronoun 'who'.

Here the words 'sort of a man' refers to the nature of the person. And as the nature of a person is an abstract noun, we should use pronoun 'what'.

As it is not clear here that what one is doing, so we should use pronoun 'what'.

Saying something is a verb, and the doer of the action is 'subject' i.e. a person. For a person, we use 'who'.

For referring to persons we use pronoun 'who' (in subjective case) and 'whom' (in objective case). As the doer of the action is 'you' and not the person that qualifies the blank, so for the blank we should use objective case i.e. 'whom'.

Knowing something is a verb (verb of being). For doer of a verb, we use pronoun 'who'.

Whenever we start a sentence with a pronoun referring to more than one person, we use 'which' as the pronoun.

Whenever we refer to profession of a person, we use the pronoun 'what' as an interrogative.

Here the aim of life is an abstract noun, and for abstract nouns we use pronoun 'what'.

For living nouns we use pronoun 'who' (in subjective case) and 'whom' (in objective case). In the given sentence, subject is 'you', and the person he/she met is an objective case. As the blank qualifies to the latter, therefore, option 1.