Final answer:
In Java, the string ",\s*" represents the regular expression which matches a comma followed by zero or more whitespace characters. Option a is the correct Java string that represents this regular expression.
Step-by-step explanation:
The Java strings that represent the regular expression ,\s* (a comma followed by zero or more whitespace characters) from the given options are:
- a. ,\s*
- b. ,\s+
- c. ,\s\*
- d. .\s*
Option a is the correct answer. The expression ,\s* matches a comma followed by zero or more whitespace characters. In Java strings, \s matches a single whitespace character, and * is a quantifier that means "zero or more instances of the preceding element". Therefore, the string ",\s*" exactly matches the regular expression in question.