The value NaN (Not-a-Number) is a special numeric value that results from an operation that cannot produce a meaningful number.

In option B, parseInt('two') attempts to parse a string that does not begin with a numeral. The function cannot convert 'two' into an integer and therefore correctly returns NaN.

In option C, the division operator (/) triggers numeric type coercion on the string 'five'. Since 'five' cannot be converted into a valid number, it is coerced to NaN. Any arithmetic operation involving NaN as an operand results in NaN.

A. Number('5') successfully converts the string to the number 5. The expression 10 / 5 evaluates to 2, which is a valid number.

D. In JavaScript, division of a non-zero number by 0 does not result in NaN. Instead, it evaluates to Infinity.

1. ECMAScript® 2023 Language Specification (ECMA-262

14th edition):

For parseInt (Option B): Section 19.2.5

parseInt ( string

radix )

describes the parsing process. If the input string does not contain any mathematical integer value

the result is NaN.

For Division and Type Coercion (Option C): Section 13.7

Multiplicative Operators

specifies that for the division A / B

both operands are first converted to numbers using the ToNumeric abstract operation. The string 'five' converts to NaN

and as per Table 22

Number / NaN results in NaN.

For Division by Zero (Option D): Section 6.1.6.1.5

Number::divide ( x

y )

states that if x is finite and non-zero and y is +0

the result is +Infinity.

2. MDN Web Docs (Official Mozilla Documentation for JavaScript):

parseInt(): "If the first character cannot be converted to a number

parseInt() returns NaN." (Source: MDN Web Docs

parseInt()

"Return value" section).

NaN: "NaN is a property of the global object. It is a value representing Not-A-Number. ... It is the returned value when Math functions fail (e.g.

Math.sqrt(-1)) or when a function trying to parse a number fails (e.g.

parseInt('blabla'))." (Source: MDN Web Docs

NaN

"Description" section).

Arithmetic Operators: "If one of the operands is a string that cannot be converted to a number

the result is NaN." (Source: MDN Web Docs

"Arithmetic operators"

"Division (/)" section).