In this vocabulary and collocation question, choose the most appropriate adjective to complete the sentence: "The relation between the Indian P.M. and the U.S. President is perfectly ________."

Introduction / Context:
This question tests your understanding of collocations used in diplomatic and political contexts. The sentence is: "The relation between the Indian P.M. and the U.S. President is perfectly ________." You must pick the adjective that best describes a positive, friendly relationship between high level political leaders in formal English.

Given Data / Assumptions:

• Sentence: "The relation between the Indian P.M. and the U.S. President is perfectly ________."
• Option A: "excellent"
• Option B: "smooth"
• Option C: "informed"
• Option D: "cordial"
• The context is international political relations and diplomacy.

Concept / Approach:
In diplomatic language, the most common adjective to describe a friendly, respectful official relationship is "cordial". We often read phrases such as "cordial relations between two countries" or "a cordial meeting between leaders". The word "excellent" is a general positive adjective, but "perfectly excellent" is slightly awkward and "excellent relation" is less idiomatic than "cordial relations". "Smooth" can describe processes, operations, or journeys but is not the first choice for high level political relations. "Informed" describes a person or decision that has good information, not a relationship. Therefore, "cordial" is the most appropriate and widely accepted term here.

Step-by-Step Solution:
Step 1: Identify the context: political or diplomatic relations between two heads of state or government.Step 2: Recall common collocations like "cordial relations", "friendly relations", and "warm relations" between countries and leaders.Step 3: Evaluate each option. "Cordial" directly matches the standard collocation "cordial relations".Step 4: Insert "cordial" into the sentence: "The relation between the Indian P.M. and the U.S. President is perfectly cordial."Step 5: Confirm that the resulting sentence is natural and consistent with diplomatic language used in news and reports.

Verification / Alternative check:
We can test other options. "The relation is perfectly excellent" sounds redundant and is not a standard phrase in political reporting. "The relation is perfectly smooth" could theoretically describe the absence of conflict, but it is not a common way to describe diplomatic ties. "The relation is perfectly informed" is incorrect because relationships themselves are not "informed"; people or decisions are. Diplomatic reports typically speak of "cordial and cooperative relations", confirming that "cordial" is the best match.

Why Other Options Are Wrong:

• Option A "excellent" is a positive adjective but does not form the most idiomatic collocation with "relation" in formal diplomacy.
• Option B "smooth" is more suited to describing procedures, negotiations, or operations rather than the overall relationship.
• Option C "informed" is used for people or opinions, not for describing a relationship between two leaders.

Common Pitfalls:
Students often rely on general positive adjectives like "good" or "excellent" without considering the specific context and typical collocations. Exam setters frequently test whether you know the exact words that naturally go together in formal English. Reading newspapers and editorials dealing with international relations can help you become familiar with terms like "cordial", "bilateral", "strategic", and "amicable" in connection with relations between countries.

Final Answer:
The most appropriate adjective is "cordial", giving the sentence: "The relation between the Indian P.M. and the U.S. President is perfectly cordial."