Conditional data masking in Snowflake allows for dynamic masking of column values based on specific conditions, typically evaluated against other columns or user context. Option D is correct because it accurately describes how conditional masking policies can reference other columns to determine whether to mask data (e.g., masking salary only if department is 'HR'). Option A is incorrect because conditional masking applies to any data type, not just plain text. Option B is partially descriptive but vague; conditional masking can target multiple columns but the key feature is the condition-based evaluation. Option C is incorrect because conditional masking does not mask all values uniformly—it applies masking selectively based on conditions. The community discussion supports D, with the highest upvoted comment (4 upvotes) linking to Snowflake documentation on conditional masking based on subqueries from other tables.