Final answer:
For a start-up with high demand and limited resources handling e-commerce messages, a triggered automation for transactional messages is the best scalable solution.
Step-by-step explanation:
The best recommendation for a start-up meal delivery company facing high demand and limited resources in managing e-commerce messages is b) A triggered automation to send transactional messages. This system can automatically send an email confirming each individual order or subscription as soon as the customer completes the transaction, without manual intervention each time. As the business scales, this automated system will handle the increased volume of transactions efficiently, maintaining a professional level of customer service and communication.