Step 1: Understanding the Formation of Erosional Landforms.
Erosional landforms are primarily formed by the processes of weathering, transportation, and erosion by wind, water, or ice.
Step 2: Analyzing the Options.
- Cirque and ventifact are both formed by erosion. A cirque is a bowl-shaped depression carved by glaciers, while a ventifact is a rock shaped by wind erosion.
- Loess and yardangs are wind-driven formations but are not primarily erosional in nature.
- Barchans and till are related to wind and glacial deposits, not primarily erosional processes.
- Moraine and eskers are depositional landforms formed by glacial action, not erosional.
Thus, the correct answer is (A) Cirque and ventifact.
Final Answer:
\[
\boxed{\text{Cirque and ventifact}}
\]