The correct answer is: D. no article
The Himalayas are the highest mountain range in the world, and they are located in Asia. They are a mountain range that runs along the border between Nepal and China. The Himalayas are a very important mountain range because they provide water for many people and animals. They also provide a home for many different plants and animals.
The Himalayas are so long that they are often referred to as “the Himalayas” without any article. This is because they are a single, continuous mountain range. If we were to refer to a specific part of the Himalayas, we would use an article. For example, we might say “the Mount Everest region of the Himalayas” or “the Ganges River valley in the Himalayas.”
The other options are incorrect because they are all articles. An article is a word that is used to modify a noun. The articles “a” and “an” are used to refer to singular nouns that are not specific. The article “the” is used to refer to singular nouns that are specific. In this case, we are not referring to a specific part of the Himalayas, so we do not need to use an article.