In the following passage, some of the words have been left out. Read the passage carefully and select the correct option for the given blank. This was enough __________ the book store owner turned librarian Husain to assess its valuable contents.

Introduction / Context:
The question is part of a cloze test, where you must choose the most appropriate preposition to complete a sentence logically and grammatically. The sentence describes how something provided sufficient information for a person to make an assessment of a book’s contents. Such preposition questions test collocation and natural usage in English.

Given Data / Assumptions:

• Sentence: This was enough __________ the book store owner turned librarian Husain to assess its valuable contents.
• Subject of reference: "This" refers to some information, probably the preface or a small portion of the book.
• The person affected: the book store owner turned librarian Husain.
• The verb phrase: "was enough for someone to do something" is a common pattern.

Concept / Approach:
In English, "enough for someone to do something" is a standard construction. For example, "It was enough for me to decide" or "This evidence is enough for the jury to convict." The preposition "for" introduces the person who is in a position to act based on the sufficiency of something. The other prepositions do not fit naturally in this pattern and would significantly alter or break the structure.

Step-by-Step Solution:
Step 1: Identify the common collocation: "enough for someone to act." Step 2: Insert "for" in the blank: "This was enough for the book store owner turned librarian Husain to assess its valuable contents." Step 3: Check if the sentence is grammatically complete and meaningful with "for." Step 4: Test the other prepositions mentally ("enough of," "enough to," "enough from") and see that they either distort or break the sentence. Step 5: Confirm that "for" is the only choice that preserves normal English structure.

Verification / Alternative check:
Consider similar sentences: "The short summary was enough for the editor to understand the theme," or "Her expression was enough for him to realise the truth." In all such sentences, "for" introduces the person who reacts. The sentence in the passage follows exactly the same pattern, which supports the choice.

Why Other Options Are Wrong:

• of: "Enough of the book store owner" would change the meaning completely and does not fit the required structure.
• to: "Enough to the book store owner" is not idiomatic English; the phrase "enough to" is used before a verb, not before a person.
• from: "Enough from the book store owner" suggests that the owner is the source of something, which does not match the context of assessing contents.

Common Pitfalls:
A frequent error is to rely only on literal meaning and choose "to" because it appears before a verb later in the sentence. However, the preposition in the blank must connect "enough" to the person, not to the action. Remembering set patterns like "enough for someone to do something" helps avoid such mistakes in cloze tests.

Final Answer:
The correct preposition to complete the sentence is for.