In Snowflake, variables are denoted using the dollar sign ($) character. This is clearly documented in Snowflake's official documentation for session variables, where it states that variables must be prefixed with a$ sign to distinguish them from bind parameters and other identifiers. The community discussion shows 100% consensus on option C, with multiple users confirming this is correct and providing references to the official documentation. The other options (@, &, #) are not used for denoting variables in Snowflake SQL.