APIKIt Creates a separate flow for each HTTP method. Hence 4 private flows would be generated.
MuleSoft Documentation Referrence : https://docs.mulesoft.com/mule-runtime/4.3/build-application-from-api

Correct answer is [[5, 10, 15, 20], 5]
Key thing to note here is that any changes made to payload in for each loop are not available outside for each scope where as variable value updated in for each loop is visible out side for each loop too.