Answer:
1.transactional model
Step-by-step explanation:
Transactional models are related to a system where it is possible to send and receive messages simultaneously. These models are usually triggered by certain actions on a website or application. Marketers generally refer to it as a transactional model, but in reality, the transactional model is only a fraction of the triggered messages.
The purpose of this type of model is to assure the customer that a process has been initiated or completed. For this reason, you need to automate this process so that you can send the right messages to the right person at the right time and receive messages from them at any time.