A Solutions Architect Must Create a Highly Available Bastion Host

A solutions architect must create a highly available bastion host architecture. The solution needs to be resilient within a single AWS Region and should require only minimal effort to maintain. What should the solutions architect do to meet these requirements?

A) Create a Network Load Balancer backed by an Auto Scaling group with a UDP listener.
B) Create a Network Load Balancer backed by a Spot Fleet with instances in a partition placement group.
C) Create a Network Load Balancer backed by the existing servers in different Availability Zones as the target.
D) Create a Network Load Balancer backed by an Auto Scaling group with instances in multiple Availability Zones as the target.