Which of the following is a valid identifier in Java?Options_identifier123identifier#identifieridentifier-123

The valid identifier in Java from the given options is "identifier123".

In Java, a valid identifier can start with a letter, a dollar sign ($), or an underscore (_). After the first character, an identifier can have any combination of characters. A keyword cannot be used as an identifier.

Most importantly, in Java, identifiers are case sensitive.

Here's why the other options are not valid:

• "identifier" is not valid because it starts with an underscore ().
• "identifier#" is not valid because it contains a hash (#) symbol.
• "identifier-123" is not valid because it contains a hyphen (-).

So, the only valid identifier in the given options is "identifier123".