What type of response indicates that a plan is understood and logical?

The response that indicates a plan is understood and logical is "It's logical." This phrase directly acknowledges that the plan makes sense and follows a reasonable line of thought, suggesting that the person reviewing the plan comprehends its content. When someone states that something is logical, it implies they have carefully considered the details and found that the reasoning is sound and coherent. This not only shows understanding but also provides a positive assessment of the plan's rationale and structure.

In contrast, statements like "It's marvelous" or "It's unrealistic" may express strong opinions but do not specifically address the clarity or logic of the plan. Saying "It's unclear" indicates confusion rather than understanding, and "It's unrealistic" suggests impracticalities rather than a logical assessment.