You need to configure connectors between each routing group. What are two possible ways to achieve this goal？（）
- ACreate and configure SMTP connectors between the routing groups. Do not create additional connectors between the routing groups
- BCreate and configure routing group connectors between the routing groups. Do not create additional connectors between routing groups
- CCreate and configure low-cost group connectors and high-cost SMTP connectors between the routing groups
- DCreate and configure high-cost routing group connectors and low-cost SMTP connectors between the routing grou