Which of the following indicates that a soil is provisionally suitable?

The indication that a soil is provisionally suitable is reflected by wetness conditions between 36 and 48 inches. This level of wetness suggests that while there may be water present in the soil, it is not at a depth that would typically inhibit the functionality of a septic system. Ideally, septic systems require certain depth thresholds regarding wetness to ensure proper drainage and treatment of effluent, which means that if the wetness is deeper than 36 inches but does not reach the surface, the site may still be considered for use with some precautions.

Other choices highlight conditions that could impair soil suitability. Lateral water movement within 36 inches could indicate that water is moving horizontally at a shallow depth, which might lead to saturation issues in a septic system. A soil surface less than 30 inches indicates a shallowness which may expose the system to surface water or create limitations for adequate drainage, making it less favorable for septic use. Therefore, the conditions described in the correct response indicate a more favorable scenario for septic system installation as compared to the other options provided.