The sentence "He is captain of the team" does not require an article before the noun "captain." Titles or positions don't usually need articles before them when used in a general sense. However, the other options require articles before the nouns for correct grammar: "a doctor," "the hospital," and "a new laptop."

Additional Fact:
Understanding when to use articles, especially before titles, professions, or positions, helps in constructing grammatically accurate sentences.

Explanation:

The correct answer is option A: "He is captain of the team."

Definite and indefinite articles:
In English, articles are used to indicate whether a noun refers to a specific or non-specific item or items. There are two types of articles: definite and indefinite.

- The definite article "the" is used to refer to a specific noun that is already known or has been previously mentioned.
- The indefinite articles "a" and "an" are used to refer to non-specific nouns, indicating that there is one of something or an unspecified item.

No article:
However, there are also cases where no article is required before a noun. Here are some situations where no article is used:

1. Generalizations:
When making generalizations or stating general truths, no article is used. For example:
- "Dogs are loyal animals."
- "Books are a great source of knowledge."

2. Occupations and titles:
When referring to someone's occupation or title, no article is used. For example:
- "She is a doctor."
- "He is president of the company."

3. Places and institutions:
When referring to places or institutions in a general sense, no article is used. For example:
- "She goes to school every day."
- "He works at university."

Identifying the correct sentence:
In the given options, the correct sentence that requires no article is option A: "He is captain of the team." This sentence refers to someone's title or role, which does not require an article.

Let's analyze the other options:

Option B: "She is studying to become doctor."
This sentence is incorrect because it is missing the indefinite article "a" before the noun "doctor." The correct sentence should be "She is studying to become a doctor."

Option C: "They went to hospital to visit a friend."
This sentence is incorrect because it is missing the definite article "the" before the noun "hospital." The correct sentence should be "They went to the hospital to visit a friend."

Option D: "I need to buy new laptop."
This sentence is incorrect because it is missing the indefinite article "a" before the noun "laptop." The correct sentence should be "I need to buy a new laptop."

In conclusion, the sentence that requires no article is option A: "He is captain of the team."