An architect is designing a connectivity solution for a customer's two small branch offices. The customer wants a cost-effective design, no routing overhead, and some down time during the year is…

A single-homed design, involving a single connection to a service provider, is the most cost-effective option, introduces the least routing overhead, and inherently implies that some downtime is tolerable, fulfilling all customer requirements.

Dual multihomed designs involve multiple connections to multiple service providers, offering high redundancy and increased complexity, which is neither cost-effective nor low on routing overhead.

Single multihomed refers to multiple connections to a single service provider, which offers some redundancy but increases cost and complexity compared to a single-homed setup, not aligning with the 'most cost-effective' requirement.

Dual-homed solutions typically involve two connections to one service provider or device, providing more redundancy but also incurring higher costs and more routing considerations than a single-homed design.