Which statement correctly describes the identifiers that may include underscores but not spaces or symbols?

Which statement correctly describes the identifiers that may include underscores but not spaces or symbols?

• A. Spaces are allowed
• B. No spaces or symbols are allowed
• C. Only letters and numbers are allowed
• D. Underscores are allowed in names

Answer: (D)

Identifiers label variables, functions, and other elements, and the characters you can use in them are letters, digits (usually after the first position), and underscores. Spaces and most symbols are not allowed because they would either split the name into separate tokens or have special meaning in the language. That’s why underscores being allowed in names matches how identifiers are usually formed—it lets you include a readable separator like snake_case without introducing spaces. The other statements contradict this pattern: spaces aren’t allowed, and some imply only letters and numbers can be used (which excludes underscores). So, the description that underscores may appear in names best captures how identifiers are typically defined.

Identifiers label variables, functions, and other elements, and the characters you can use in them are letters, digits (usually after the first position), and underscores. Spaces and most symbols are not allowed because they would either split the name into separate tokens or have special meaning in the language. That’s why underscores being allowed in names matches how identifiers are usually formed—it lets you include a readable separator like snake_case without introducing spaces. The other statements contradict this pattern: spaces aren’t allowed, and some imply only letters and numbers can be used (which excludes underscores). So, the description that underscores may appear in names best captures how identifiers are typically defined.