Which of the following options relates to optimizing query performance in relation to null keys?

Adding indexes and foreign keys directly contributes to optimizing query performance, particularly when dealing with null keys in a database. Indexes allow the database management system to locate and access data more efficiently, reducing the amount of time it takes to execute queries that involve searching for records. This is especially relevant when null keys are present, as they can complicate the process of querying data, potentially leading to slower response times if the database engine has to scan through a larger dataset without proper indexing.

When foreign keys are used, they not only establish relationships between tables but also can help optimize query performance. Foreign keys often imply that certain fields will be used in joins or lookups, and having an index on these fields ensures that the database can perform these operations more quickly.

While improving network latency, data normalization, and adjusting server settings can also play roles in overall performance, they do not directly optimize the querying process concerning null keys as effectively as the use of indexes and foreign keys does. Therefore, the correct choice highlights a more targeted approach to enhancing query efficiency in scenarios where null keys may be a factor.