In each of the question given below, a statement has been given with a blank. Some words or phrases have been given in the options following the statement. Choose the most appropriate word or phrase that could fit in the statement to make it contextually meaningful and grammatically correct.

The ______________ of the business deal made the investor suspicious, so he asked for a more specific outline of the plan.

The correct answer is vagueness.

Step-by-Step Explanation:

1. Analyze the Context:
The sentence describes a situation where an investor becomes suspicious about a business deal and requests a "more specific outline of the plan."
The phrase "asked for a more specific outline" indicates that the current outline or description of the deal is lacking detail, precision, or clarity.

2. Evaluate the Options:
* plainness: Refers to being simple, clear, or unadorned. If a deal was plain, it would be easy to understand, which does not align with the investor's suspicion or request for details.
* vagueness: Refers to a lack of preciseness, clarity, or detail. If the business deal is vague, it is unclear, which naturally makes an investor suspicious and prompts a request for a more specific plan. This fits the context perfectly.
* obviousness: Refers to being easily perceived or understood. An obvious deal would not require a more specific outline.
* clarity: Refers to clearness or coherence. A clear deal would not cause suspicion or lead to a request for more details.

3. Conclusion:
Therefore, "vagueness" is the only word that is both grammatically correct and contextually meaningful in the blank.