In which way does a spine-and-leaf architecture allow for scalability in a network when additional access ports are required?

In which way does a spine-and-leaf architecture allow for scalability in a network when additional access ports are required?

A. A spine switch and a leaf switch can be added with redundant connections between them. B. A spine switch can be added with at least 40 GB uplinks. C. A leaf switch can be added with connections to every spine switch. D. A leaf switch can be added with a single connection to a core spine switch.