AWS Certified Solutions Architect Professional SAP-C02 Practice Question

Regional Standard Reserved Instances automatically apply their discount across all Availability Zones in the Region and provide instance-size flexibility for Linux/Unix usage. When the reservations are purchased in the management (payer) account with sharing enabled, the discount is first applied to that account and then to any linked account, so all three accounts benefit without additional administration. Standard RIs offer a No Upfront payment option, and a three-year No Upfront term delivers a larger effective discount than Convertible RIs or a Compute Savings Plan while avoiding an up-front cash outlay.

Zonal Standard RIs would lock the company into specific Availability Zones, provide capacity reservations that are not required, and-when bought All Upfront-violate the up-front-cost constraint. Convertible RIs meet the functional requirements but offer a smaller discount than Standard RIs, so they do not minimize cost. A Compute Savings Plan also offers less discount (up to 66 %) than a three-year Standard RI and provides more flexibility than the workload needs. Therefore, purchasing three-year, No Upfront, Region-scoped Standard Reserved Instances in the management account is the most cost-effective solution.