Which statement is TRUE concerning eligibility requirements?

Each of the statements provided accurately reflects key details regarding eligibility requirements in the context of governmental grants and accounting principles.

The first statement highlights that a requirement for resources to be sold during a specific timeframe qualifies as a time requirement. This is true because it imposes a limitation on when transactions involving those resources can occur to ensure compliance with the grant's timing stipulations.

The second statement indicates that a requirement preventing the use of resources before a designated period is also a time requirement. This aligns with the definition of time conditions in grant agreements, as it outlines periods during which the resources must remain untouched to fulfill the terms of the grant.

The third statement addresses the situation where no explicit time requirement is set by the grantor. In such instances, it is important to impute an appropriate time requirement to establish the terms under which the resources should be utilized. This maintains clarity and accountability in the management of grant funds.

Given that all these statements accurately convey the nature of eligibility requirements concerning timing, the choice that encompasses all these points is indeed the correct response.