To validate a pattern matching input, the correct validation control to use is the "RegularExpressionValidator."
Let's go through each option to understand why it is correct or incorrect:
Option A) FieldValidator - This option is incorrect because the FieldValidator control is used to check if a required field is filled or not. It does not validate pattern matching.
Option B) RegularExpressionValidator - This option is correct. The RegularExpressionValidator control is used to validate input against a specified regular expression pattern. It is commonly used to validate pattern matching for fields like email addresses, phone numbers, or zip codes.
Option C) RangeValidator - This option is incorrect. The RangeValidator control is used to validate if the input value falls within a specified range of values. It does not validate pattern matching.
Option D) PatternValidator - This option is incorrect. There is no validation control named PatternValidator in ASP.NET. The correct control for pattern matching validation is the RegularExpressionValidator.
The correct answer is B) RegularExpressionValidator. This option is correct because it is specifically designed to validate pattern matching using regular expressions.