Which of the following cannot be used as a valid identifier in Python?

Correct option is A

In Python, identifiers are names used to identify variables, functions, classes, or other objects. The rules for valid identifiers in Python are:
1. An identifier must start with a letter (A-Z or a-z) or an underscore (_).
2. The rest of the identifier can contain letters, digits (0-9), and underscores.
3. Identifiers cannot start with a digit.
Given the options:
· (a) 1stName: This is invalid because the identifier starts with a digit (1), which is not allowed in Python.
· (b) Name1: This is valid because it starts with a letter and contains a digit, which is allowed.
· (c) Name_1: This is valid because it starts with a letter and contains an underscore and a digit, which are allowed.
· (d) FirstName: This is valid because it starts with a letter and contains only letters.
Important Key Points:
1. Identifiers cannot start with digits. They can only start with letters or underscores.
2. Underscores and digits are allowed after the first character.
Knowledge Booster:
· Identifiers like _variable are valid, as the underscore is considered a valid starting character.
· Python identifiers are case-sensitive, meaning name and Name are treated as different identifiers.