An instruction of thick acid lava, which forces overlaying sedimentary rock layers to bulge into a dome, may cool and solidify to form a

Analyze the question: The question describes an intrusion ("instruction" is a typo for intrusion) of thick, viscous acid lava. It pushes the overlying sedimentary layers upward into a dome shape. We need the igneous landform that forms when it cools.

Concept: Intrusive igneous features

• Batholith: A huge, irregular mass of magma that cools deep in the crust. It forms the core of mountain ranges and does not make a neat local dome.
• Laccolith: A mushroom- or dome-shaped intrusion. It forms when thick, viscous (acidic) magma is injected between sedimentary layers. It has a flat base and arches the layers above into a dome.
• Dyke: A vertical or steeply inclined sheet of magma that cuts across rock layers. It does not bulge them into a dome.
• Lopolith: A saucer-shaped (concave) intrusion. The rock layers sag downward instead of bulging upward.

Step-by-step solution:

1. The lava is thick and acidic, so it is viscous and cannot flow far.
2. It is forced between sedimentary layers, so it forms a concordant intrusion.
3. It pushes the overlying layers upward into a dome, which is the signature feature of a laccolith.
4. The batholith is too large and deep, the dyke is discordant (vertical), and the lopolith is concave (saucer-shaped), so none of these fit.

Answer: B. Laccolith

Exam tip: Remember "Lacco = Lump" (dome upward) and "Lopolith = Low" (saucer sagging downward). Thick, viscous lava produces a dome-shaped laccolith.