B is correct.
A is not correct because outbound message mean: fire & forget => no callback => wrong
C is manual solution => not recomment.
D is not a good solution, a lot of risks when system have many quote need to be generate => should using batch instead to remove the risk when working with multiple record at a time.
=> B is the best solution with batch & scheduled.

D

The reason for this is that a workflow-initiated Apex allows for direct access to the Salesforce data and the ability to make a synchronous callout to the external quote engine. This would ensure that the latest account, contact, and contract information is retrieved and sent to the quote engine in a timely manner, meeting the VP's requirement of sending the quote one week prior to contract expiration. Additionally, Apex code can handle any data manipulation or formatting that may be required before sending the information to the quote engine.

B seems correct to me as it is more direct

I felt A should be a better solution