Refer to the exhibit. This network is running EIGRP as the routing protocol and the internal networks are being advertised in EIGRP. Based on the link speeds, all traffic between London and Rome is…

Configuring EIGRP route summarization on all interfaces causes routers to advertise a single summary route instead of individual subnet entries, which minimizes the number of routes exchanged throughout the EIGRP domain and reduces routing table size on all routers.

Filtering routes on the London-Barcelona link would disrupt the primary high-speed traffic path between those sites and could cause connectivity issues, which contradicts the design goal.

Filtering routes on the London-Rome link would suppress route advertisements over that link entirely, preventing its use rather than enabling the selective utilization the design requires.

Configuring route leaking of specific summary routes on the London-Rome link allows targeted prefixes to be advertised over that direct path, overriding the summarization suppression and giving London a more specific route to certain Rome networks via the direct link, thus enabling selective utilization of that otherwise idle connection.