Which of the following are not keywords?(A) NULL(B) implements(C) protected(D) extended(E) string
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(D) & (E)
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(A), (D) & (E)
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(D)
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(C), (D) & (E)
In Java, NULL (should be null), extended (should be extends), and string (String is a class) are not keywords. 'implements' and 'protected' are valid Java keywords. Option B correctly identifies the three items that are not keywords.
To answer this question, we need to understand what keywords are in the context of programming languages. Keywords are reserved words that have special meaning in a programming language and cannot be used as identifiers.
Let's go through each option to understand why it is correct or incorrect:
Option A) (D) & (E) - This option is incorrect. Both "extended" and "string" are keywords in some programming languages. "extended" is a keyword used in Java to indicate that a class is inheriting from another class, and "string" is a keyword used in several programming languages to represent a data type that stores a sequence of characters.
Option B) (A), (D) & (E) - This option is correct. "NULL" is not a keyword in most programming languages. It is often used to represent a null value or absence of a value, but it is not a reserved word. Both "extended" and "string" are keywords, as explained above.
Option C) (D) - This option is incorrect. As mentioned earlier, "extended" is a keyword in some programming languages.
Option D) (C), (D) & (E) - This option is incorrect. "protected" is a keyword in many programming languages, including Java and C++. It is used to specify that a member (e.g., variable or method) of a class can be accessed by subclasses.
The correct answer is option B. "NULL" is not a keyword, while "extended" and "string" are keywords in some programming languages.