Which two statements about a spine-and-leaf data center design are true? (Choose two.)
A. A spine switch corresponds to an access switch in a traditional data center design.
B. The design is a two-tier architecture.
C. A leaf switch corresponds to an access switch in a traditional data center design.
D. All spine switches connect directly to one another.
E. The design is a three-tier architecture.
B & C are correct here
Indeed. B & C are the correct answers.
Although Spine switches potentially could be connected directly together that is generally not the case.
“In this two-tier Clos architecture, every lower-tier switch (leaf layer) is connected to each of the top-tier switches (spine layer) in a full-mesh topology. The leaf layer consists of access switches that connect to devices such as servers.”
https://www.cisco.com/c/en/us/products/collateral/switches/nexus-7000-series-switches/white-paper-c11-737022.html