Geographers classify landforms into different orders based on their scale and origin.
First-order landforms are the largest and are on a global scale. They consist of the continental landmasses and the ocean basins.
Second-order landforms are the major features found on the continents and in the oceans. On the continents, these include mountains, plains, and plateaus.
Third-order landforms are smaller, more localized features created by erosion and deposition, such as rivers, valleys, beaches, and deltas.
The question asks for second-order landforms. Based on the classification, mountains, plains, and plateaus fit this category.
Therefore, option (C) is the correct answer.