Explanation
Option B is a correct finding, because it means that the company can use their cloud-based ETL tools to extract data from the legacy systems via the APIs exposed by the on-premise middleware, transform the data as needed, and load the data into Salesforce using queues. Queues are a way of managing asynchronous operations, such as bulk data loading, by placing them in a queue and executing them when resources are available1.
Option C is also a correct finding, because it means that the company can expose their legacy data to the cloud via their on-premise middleware APIs. APIs are a way of enabling communication and data exchange between different systems using standard protocols and formats2. By providing APIs to access their legacy data, the company can use any cloud-based tool or application that can consume those APIs to retrieve and manipulate the data.
Option A is not a correct finding, because it means that the company cannot access their legacy data from the cloud, which prevents them from using their cloud-based ETL tools or any other cloud-based integration solution. If only on-premise systems are allowed to access the legacy systems, then the company would need to use an on-premise integration tool or application to copy the data to Salesforce.
Option D is not a correct finding, because it does not affect the ability to copy legacy data in Salesforce.
Queues are useful for on-premise integration, but they are not necessary for copying data to Salesforce. The company can use other methods, such as direct API calls or batch processes, to load data into Salesforce without using queues.
References: 1: Queueable Apex | Apex Developer Guide | Salesforce Developers 2: API Basics | SOAP API Developer Guide | Salesforce Developers