BirthDate: The default() masking function is used to apply a predefined mask based on the column's data type. For date or datetime data types, the default() function masks the value to 1900-01-01, which precisely matches the requirement.

EmailAddress: The partial(prefix, padding, suffix) function is used to mask string data, exposing a specified number of characters at the beginning (prefix) and end (suffix), while replacing the middle section with a padding string.

• The requirement is to show the "first leading character," so prefix = 1.
• The requirement is to show the "last five characters," so suffix = 5.
• The option 'partial(1, "@", 5)' correctly implements this logic, using "@" as the padding string. The email() function is incorrect as it has a fixed format (first letter and .com suffix) that does not match the "last five characters" requirement. The random() function is incorrect as it is only used for numeric data types.

Microsoft Fabric Documentation (Dynamic Data Masking):

default() function: "For date/time data types (date, datetime2, datetime, datetimeoffset, smalldatetime, time), default() masks with 1900-01-01 00:00:00.0000000 (or corresponding value for date or time)."

Source: Microsoft Learn. (2024). Dynamic data masking in Microsoft Fabric data warehousing. Section: "Dynamic data masking built-in masking functions", Subsection: "default()".

partial(prefix, padding, suffix) function: "Masking method that exposes the first and last characters according to the specified prefix and suffix values and a custom padding string... prefix [is the] Number of characters at the beginning to expose. ... suffix [is the] Number of characters at the end to expose."

Source: Microsoft Learn. (2024). Dynamic data masking in Microsoft Fabric data warehousing. Section: "Dynamic data masking built-in masking functions", Subsection: "partial(prefix, padding, suffix)".

random(start, end) function (Incorrect Option): "Use the random function to mask any numeric data type with a random value within a specified range."

Source: Microsoft Learn. (2024). Dynamic data masking in Microsoft Fabric data warehousing. Section: "Dynamic data masking built-in masking functions", Subsection: "random(start, end)".