Vibe Coder Assessment

You're building an online order processing system. A user's "place order" request needs to be completed sequentially by three independent microservices: Service A (validates user identity and payment method), Service B (queries inventory and locks stock), and Service C (creates order record and sends confirmation to user). You find that while each service executes its core logic quickly (about 50 milliseconds), the end-to-end total time from when users click "place order" to receiving confirmation often exceeds 600 milliseconds, which significantly impacts user experience during peak periods.

Facing this latency problem caused by multiple internal services in series, as the sole decision-maker of the team, what is your primary technical optimization direction?