In the sentence "In India, Hindi is the most _______ spoken language", which word best completes the blank?

Introduction / Context:
This question checks your understanding of common adverb collocations in English, especially with the phrase most _______ spoken language. The sentence refers to Hindi in India and asks which adverb naturally and correctly describes the extent of its use across people and regions. Only one of the options is regularly used with spoken language in this way.

Given Data / Assumptions:

• The sentence is: In India, Hindi is the most _______ spoken language.
• Profusely usually means in large quantities, often with things like apologies, thanks, or blood.
• Richly can mean in a rich or ornate manner.
• Deeply often refers to emotions or degrees, as in deeply moved.
• Widely means over a large area or among many people.

Concept / Approach:
When we talk about how common a language is in terms of number of speakers or geographic spread, we use the phrase widely spoken language. This describes a language that is spoken by many people over a broad region. None of the other adverbs fits this collocation: we do not say profusely spoken, richly spoken, or deeply spoken language. The question is clearly about prevalence, so widely is the natural and correct choice.

Step-by-Step Solution:
Step 1: Focus on the idea being expressed: Hindi is spoken by many people throughout India.Step 2: Recall standard phrases such as widely spoken, widely used, or widely known.Step 3: Test widely in the blank: In India, Hindi is the most widely spoken language. This sounds idiomatic and fully correct.Step 4: Test profusely; profusely spoken language is not a common or meaningful expression.Step 5: Test richly and deeply; neither richly spoken nor deeply spoken are conventional ways to talk about the distribution or prevalence of a language. Therefore, widely is the only appropriate option.

Verification / Alternative check:
Look at similar sentences: English is one of the most widely spoken languages in the world. Spanish is widely spoken in Latin America. These sentences match widely with spoken, emphasising large numbers of speakers and broad geographic coverage. Using any of the other adverbs in such sentences would seem odd or incorrect. This pattern confirms that widely is the correct adverb for describing how many people speak a language.

Why Other Options Are Wrong:
Profusely is used with verbs like apologise profusely or bleed profusely and relates to great quantity in a specific act, not the geographical or demographic spread of language. Richly usually modifies adjectives or verbs connected to wealth, decoration, or intensity, such as richly decorated or richly deserved. Deeply applies to feelings or degrees of some quality, like deeply grateful or deeply rooted. None of these collocations work naturally with spoken language in the sense of widespread use.

Common Pitfalls:
Some exam takers choose profusely because they associate it with a lot or many. However, collocation is crucial in English: even if the broad idea of large quantity is shared, the actual word pair profusely spoken is not used in standard language. Remember to rely on familiar word combinations from reading and listening, such as widely spoken, rather than forcing less common adverbs into the blank.

Final Answer:
The blank should be filled with widely, making the sentence: In India, Hindi is the most widely spoken language (option D).