Explanation:
Here’s specifically what is happening here:
1) Payload is successfully set to “Before”
2) Is null validation is used which will pass the message only if payload is null. In this case as payload is not null, it creates an Error Object. Flow execution stops
#[error.description] = “Validation error”
3) Because no error handler is defined, the Mule default error handler handles the error
4) “Validation error” is the error message returned to the requestor in the body of the HTTP request with HTTP Status Code: 500
Reference diagram:

Explanation: File is not updated when FTP read operations is performed.

Explanation: Returns an array that is the result of applying a transformation function (lambda) to each of the elements.



The map operator is a function in Dataweave which iterates over the items in an array and outputs them into a new array. It basically accepts input as a list of items in an array and manipulates the items in the array in order to form a new array as an output.

Explanation: Empty array is returned when no rows are matched.

Explanation: 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 PropertyDescription Expression (expression)
Expression in DataWeave language to evaluate input.If the expression evaluates to true, this routing option is used:

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.

Explanation: The APIkit Router is a key message processor that validates requests against the provided definition, enriches messages (for example by adding default values to the messages) and routes requests to a particular flow. Also, the Router raises errors messages if errors occurs while routing, validating or processing the user request.

Explanation:
Correct answer is System layer System APIs provide a means for insulating the data consumers from the complexity or changes to the underlying backend systems.
MuleSoft recommends three-layered approach to API-led connectivity, highlighting the three layers:
* System APIs
* Process APIs
* Experience APIs
System APIs are the core systems of record underlying core systems of record (e.g. ERPs, key customer and billing systems, databases, etc.). Process APIs allow you to define a common process which the organization can share, and these APIs perform specific functions, provide access to non-central data, and may be built by either Central IT or Line of Business IT. And finally, the Experience APIs are the means by which data can be reconfigured so that it is most easily consumed by its intended audience, all from a common data source.
The three-layered structure allows for a seamless flow of data from systems of record to new experiences, and allows for reusability of assets rather than point to point connections. This approach provides a distributed and tailored approach to architecture, greater flexibility through loose coupling, and deeper operational visibility into what is being built.