Which is the largest country in the world by total geographical area?

Introduction / Context:
Questions about the largest and smallest countries by area, population and other simple metrics are very common in general knowledge and geography sections of competitive exams. Knowing the country with the largest land area is a basic fact that helps build a mental picture of the world map.

Given Data / Assumptions:

- The question is asking about total geographical area, not population or economic size. - Four large countries are listed as options China, United States of America, Russia and Australia. - We assume standard international area figures that include land and inland water bodies but not disputed variations.

Concept / Approach:
Russia is the largest country in the world by area, spanning Eastern Europe and northern Asia. Its total area is over 17 million square kilometres, which makes it significantly larger than Canada, China, the United States and Australia. Among the options given, Russia clearly has the greatest land area and is universally recognised as the correct answer in geography references.

Step-by-Step Solution:
Step 1: Recall that Russia stretches across eleven time zones and covers a huge portion of the northern hemisphere. Step 2: Compare Russia with China and the United States, which are large but have smaller total areas than Russia. Step 3: Note that Australia, while a continent sized country, still has far less area compared to Russia and even compared to China and the United States. Step 4: Recognise that most standard lists of countries by area place Russia at rank one. Step 5: Based on this knowledge, choose Russia from the options.

Verification / Alternative check:
Any atlas, world geography textbook or trusted online ranking of countries by area shows Russia at the top of the list, followed by Canada, China and the United States. This ordering is stable and widely agreed upon by international agencies. Since Russia exceeds all others by several million square kilometres of area, there is no ambiguity about this answer.

Why Other Options Are Wrong:
China has a very large area and population but is smaller in area than Russia. The United States of America is also very large but still ranks below both Russia and Canada in total area. Australia is a vast country continent but its area is less than that of Russia, Canada, China and the United States.

Common Pitfalls:
Some learners may confuse population size with area, especially because China and India often appear at the top of population charts. Others may overlook Canada, which is not in this question but is larger than the United States. To avoid such confusion, it helps to memorise a short list of area rankings, remembering clearly that Russia is number one by area irrespective of population figures.

Final Answer:
The largest country in the world by geographical area is Russia.