What is a supported Avamar configuration?

What is a supported Avamar configuration?
A . 1 x 16 + 2 (1 utility node x 16 storage nodes) + 2 spare nodes
B . 1 x 17 (1 utility node x 17 storage nodes)
C . 1 x 1 + 1 (1 utility node x 1 storage node) + 1 spare node
D . 1 x 16 + 1 (1 utility node x 16 storage nodes) + 1 spare node

Answer: D