What type of claim is eligible for one year of retroactive effective date under the specified act?

The correct choice pertains to formal and original compensation claims being eligible for one year of retroactive effective date under the specified act. This is primarily because these types of claims are often associated with a veteran's initial request for benefits based on a service-connected disability or other factors impacting their eligibility for compensation.

When a veteran files a formal claim, they are initiating a process that allows for the potential awarding of benefits back to the date of that initial claim, provided it is determined that the claim is valid. The one-year retroactive effective date ensures that veterans receive benefits from the time they initially sought help, recognizing the importance of the claim date in relation to their eligibility for compensation.

In contrast, supplemental claims are based on new evidence after a prior claim decision and do not offer the same retroactive effective date benefit. Informal claims may not meet the criteria required for consideration as they aren’t submitted through the formal processes established, and transfer claims generally relate to benefits passed from one individual to another (such as from a servicemember to a dependent), thus also lacking applicability in this context regarding retroactive effective date.