To answer this question, you need to understand the SQL functions and their capabilities. Let's go through each option to understand why it is correct or incorrect:
Option A) TO_CHAR - This function is used to convert a number or date to a character string. It operates on specific datatypes like numbers and dates, so it cannot operate on any datatype. Therefore, Option A is incorrect.
Option B) LOWER - This function is used to convert a character string to lowercase. It operates on character strings and can be used with any datatype that can be implicitly converted to a character string. Therefore, Option B is incorrect.
Option C) LPAD - This function is used to pad a character string with a specified character to a specified length. It operates on character strings and can be used with any datatype that can be implicitly converted to a character string. Therefore, Option C is incorrect.
Option D) MAX - This function is used to return the maximum value in a column or a set of values. It can operate on any datatype, including numbers, characters, and dates. Therefore, Option D is correct.
The correct answer is D. This option is correct because the MAX function can operate on any datatype.