Which statement accurately describes the difference between null and undefined in JavaScript?

• A. Undefined means a variable has been declared but has no value; null is an explicit value assigned to indicate 'no value'. typeof null is 'object' due to a historical quirk.
• B. Undefined means a variable is forcibly null; Null means it has a value but uninitialized.
• C. Undefined and Null are identical in typeof results.
• D. Undefined is used for object properties; Null is used for arrays.

Answer: (A)

Undefined describes a value that hasn’t been assigned yet. When you declare a variable without giving it a value, its value is undefined. It also shows up when a function parameter isn’t provided or when you access an array element that doesn’t exist. Null, by contrast, is an explicit value you assign to indicate “no value right now”—you’re intentionally saying this variable should be empty.

A notable quirk is that typeof null yields 'object' in JavaScript, a historical quirk rather than a true type indication. Because of that, to check for the absence of a value you’d compare with null (for example, value === null) or use a broader falsy check if appropriate.

So, the statement that correctly captures the distinction is that undefined means a variable has been declared but has no value yet, while null is an explicit value indicating no value.