Concept:A composite cone is a volcano built of alternating layers of lava and pyroclastic materials such as ash and cinders.
Explanation:The description states "layers of ash and cinders alternating with lava." This layering is exactly the internal structure of a composite cone.
The cone is formed by repeated eruptions that deposit lava flows and volcanic fragments alternately.
It has a broad base and steep convex slopes near the summit because of the accumulation of thick, viscous lava and tephra.
A batholith and a laccolith are intrusive igneous bodies formed underground, not surface volcanic cones, so they do not match the features.
A shield volcano consists mainly of thin lava flows and has gentle, concave slopes, not alternating ash and lava layers with steep convex slopes.
Thus, the only feature with all these characteristics is a composite cone.
Answer:D. composite cone