Option 2 is the correct answer as /api/* accespts everything starting with /api/

Choice Router
The Choice router dynamically routes messages through a flow according to a set of DataWeave expressions that evaluate message content. Each expression is associated with a different routing option. The effect is to add conditional processing to a flow, similar to an if/then/else code block in most programming languages.
Only one of the routes in the Choice router executes, meaning that the first expression that evaluates to true triggers that route's execution and the others are not checked. If none of the expressions are true, then the default route executes.
Properties of <when>
PropertyDescription
Expression (expression)
Expression in DataWeave language to evaluate input.
If the expression evaluates to true, this routing option is used:
<when expression="#[vars.language == 'Spanish']" >
Mulesoft Doc Ref : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept With respect to above information , Option 1 is the correct syntax as others are incorrect because of below reasons
* Single = is not the correct syntax to validate the condition. It should be ==
* If keyword is not required in when condition.

The correct answer is To avoid duplicate processing of records in a database.
If a watermark column is provided, the values taken from that column are used to filter the contents of the next poll, so that only rows with a greater watermark value are returned. If an ID column is provided, this component automatically verifies that the same row is not picked twice by concurrent polls.
Mule doc reference : https://docs.mulesoft.com/db-connector/1.8/database-documentation#listener

Pick First is not valid type. Rest all are valid type of event processor.
Choice : https://docs.mulesoft.com/mule-runtime/4.3/choice-router-concept Round Robin : https://docs.mulesoft.com/mule-runtime/4.3/round-robin First Successful : https://docs.mulesoft.com/mule-runtime/4.3/first-successful