Why should two of each component be located at the London datacenter?

Locating two of each component, such as NetScaler Gateways and StoreFront servers, in the London datacenter provides high availability within that site (intra-site HA) by ensuring redundancy. This local resilience also supports its role in a broader multi-datacenter architecture, contributing to inter-site high availability for business continuity.

While redundant components ensure the availability of secure remote access, the primary reason for deploying two instances is high availability and fault tolerance, rather than a direct increase in security posture itself.

Deploying two components primarily aims for high availability and fault tolerance. While load balancing can maintain performance, 'increased user performance' is not the main driver compared to ensuring continuous service.

This option describes a benefit of inter-site high availability, but it doesn't fully explain why two components are specifically placed in London, which also addresses intra-site resilience. Option A is more comprehensive by covering both inter-site and intra-site HA.