Which of the following is a valid Java variable name?Question 5Answera._variableb.123variablec.variable#d. $variable

To determine which of the provided options is a valid Java variable name, let's analyze the rules for naming variables in Java:

1. Variable names must begin with a letter (a-z, A-Z), a dollar sign ($), or an underscore (_).
2. Subsequent characters may include letters, digits (0-9), dollar signs, or underscores.
3. Variable names cannot contain special characters like # or start with a digit.
4. Variable names are case-sensitive.

Now, let's evaluate each option:

1. a. _variable: Valid - starts with an underscore, followed by letters.
2. b. 123variable: Invalid - starts with digits.
3. c. variable#: Invalid - contains a special character (#).
4. d. $variable: Valid - starts with a dollar sign, followed by letters.

Final Answer

The valid Java variable names are _variable and $variable.