Step 1: Understand the role of plants in solar energy absorption.
Plants, through photosynthesis, absorb solar energy to produce food. Grass, due to its widespread presence and extensive surface area, absorbs a large amount of solar energy.
Step 2: Review the options.
- Plantation refers to the large-scale cultivation of trees, which absorbs solar energy but not as much as grasses due to their limited surface area.
- Cropping refers to the planting of various crops, but the amount of solar energy absorbed depends on the type of crop.
- Growing grass absorbs more solar energy due to the extensive coverage it provides.
- Culturing algae can absorb solar energy in aquatic environments, but it doesn't cover as much surface area as grass does on land.
Step 3: Conclude.
Growing grass absorbs the maximum amount of solar energy due to its widespread presence and extensive leaf surface area, making option (C) the correct answer.
Final Answer:
\[
\boxed{\text{Growing grass}}
\]