Networking question to reach an api server

I would like an app server "A" to reach the API server (located at Network C) via another network (network B). What is the best way to reach ? it must be a two way communication. Let me explain. Three networks are involved( Network A,B & C). What is the reliable way to design this infrastructure?

Network A [] > Network B [] and network C []

Here is what I am considering:

Create point to Site trust VPN relationship between A & B . There is Site to Site VPN between B & C that already existed . What is the reliable way App A located in Network "A" to have (port 443) two way communication to the API server in "Network C". Thank you for reading.