The Watermark delay metric is computed as the wall clock time of the processing node minus the largest watermark it has seen so far.
The watermark delay metric can rise due to:
1. Not enough processing resources in Stream Analytics to handle the volume of input events.
2. Not enough throughput within the input event brokers, so they are throttled.
3. Output sinks are not provisioned with enough capacity, so they are throttled.
Reference:
https://docs.microsoft.com/en-us/azure/stream-analytics/stream-analytics-time-handling

An auditing policy can be defined for a specific database or as a default server policy in Azure (which hosts SQL Database or Azure Synapse):
A server policy applies to all existing and newly created databases on the server.
If server auditing is enabled, it always applies to the database. The database will be audited, regardless of the database auditing settings.
Enabling auditing on the database, in addition to enabling it on the server, does not override or change any of the settings of the server auditing. Both audits will exist side by side.
Note:
The Server Audit Specification object belongs to an audit.
A Database Audit Specification defines which Audit Action Groups will be audited for the specific database in which the specification is created.
Reference:
https://docs.microsoft.com/en-us/azure/azure-sql/database/auditing-overview

OPTIMIZE_FOR_AD_HOC_WORKLOADS = { ON | OFF }
Enables or disables a compiled plan stub to be stored in cache when a batch is compiled for the first time. The default is OFF. Once the database scoped configuration OPTIMIZE_FOR_AD_HOC_WORKLOADS is enabled for a database, a compiled plan stub will be stored in cache when a batch is compiled for the first time. Plan stubs have a smaller memory footprint compared to the size of the full compiled plan.
Incorrect Answers:
A: LEGACY_CARDINALITY_ESTIMATION = { ON | OFF | PRIMARY }
Enables you to set the query optimizer cardinality estimation model to the SQL Server 2012 and earlier version independent of the compatibility level of the database. The default is OFF, which sets the query optimizer cardinality estimation model based on the compatibility level of the database.
B: QUERY_OPTIMIZER_HOTFIXES = { ON | OFF | PRIMARY }
Enables or disables query optimization hotfixes regardless of the compatibility level of the database. The default is OFF, which disables query optimization hotfixes that were released after the highest available compatibility level was introduced for a specific version (post-RTM).
Reference:
https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-database-scoped-configuration-transact-sql