Aquifer terminology and common groundwater well types Select the correct set of statements about aquifers, aquicludes, artesian versus non-artesian conditions, and ordinary gravity (water-table) wells.

Introduction / Context:
Groundwater terminology distinguishes between formations that transmit water and those that do not. Correct use of terms like aquifer, aquiclude, and water-table well is essential for hydrogeologic mapping, well design, and yield estimation.

Given Data / Assumptions:

• Standard hydrogeologic definitions are used.
• Statements relate to common near-surface formations and typical well practice.

Concept / Approach:

An aquifer is a geologic formation that is both permeable and saturated enough to yield useful water. An aquiclude (or aquitard/aquifuge depending on degree) has very low permeability and confines an underlying aquifer. A non-artesian (unconfined) aquifer has a free water surface (water table). A water-table well draws from this unconfined zone and responds to seasonal fluctuations of the water table.

Step-by-Step Solution:

Verification / Alternative check:

Introductory groundwater texts (hydrogeology) define these terms consistently; field practice labels wells by whether they are confined (artesian) or unconfined (water-table).

Why Other Options Are Wrong:

• Since (a)–(d) are all true, choosing only one is incomplete; therefore “All the above” is the only comprehensive selection.

Common Pitfalls:

• Confusing aquiclude (essentially impermeable) with aquitard (low permeability but not zero).
• Assuming any top layer is non-artesian without confirming the presence of a free water surface.

Final Answer:

All the above.