Final answer:
In SPARQL, a period at the end of a triple pattern denotes the end of that pattern within a WHERE clause and separates it from subsequent patterns. It's crucial for structuring the query and is an integral part of SPARQL syntax.
Step-by-step explanation:
In SPARQL, which is a query language for databases, a period (.) at the end of a final triple pattern serves an important function. It marks the end of that particular triple pattern within the WHERE clause of the query. The use of a period is critical in SPARQL syntax as it separates different triple patterns, indicating to the processor that one triple statement has ended and before another begins, if any. In contrast to the options provided, the period does not terminate the entire SPARQL query or denote the complement of the WHERE clause; those roles are served by other specific syntax elements.