Fill in the blank in the following sentence with suitable word given below it.
'She wanted to buy ________ books.'

The correct answer is Option A (some).

Key Points:
• Concept: Use of Quantifiers/Determiners ('Some' vs 'Any' / Distributives).
• Some is used in affirmative sentences with plural countable nouns or uncountable nouns.
• Any is primarily used in negative sentences and questions.
• Each and Neither take singular countable nouns.
• Explanation: 'She wanted to buy...' is an affirmative sentence and 'books' is a plural countable noun. Thus, 'some' is the appropriate determiner.
• Other Options: 'each' requires singular 'book'; 'neither' requires singular 'book'; 'any' is suited for negative/interrogative contexts.
• Official Key: Option 1 ('some') is the official correct answer.
• Key Takeaway: Remember: Use 'some' with plural countable nouns in positive affirmative statements.