To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) ClassCastException - This option is incorrect because ClassCastException is thrown when there is an invalid cast operation. In this case, the error is not related to casting, so ClassCastException is not the appropriate catch block.
Option B) IllegalStateException - This option is incorrect because IllegalStateException is thrown when the state of an object is invalid for the requested operation. In this case, the error is not related to the state of an object, so IllegalStateException is not the appropriate catch block.
Option C) NumberFormatException - This option is correct because NumberFormatException is thrown when an invalid string representation of a number is attempted to be converted to a numeric type. In this case, the error occurs during the parsing of the string "one" to an integer, so NumberFormatException is the appropriate catch block.
Option D) None - This option is incorrect because we need a catch block to handle the exception that may occur during the execution of the code. So, the appropriate catch block is required.
The correct answer is C) NumberFormatException. This option is correct because NumberFormatException is the appropriate catch block for handling the exception that occurs when trying to parse the string "one" into an integer.