Reading Comprehension

Read the following passage and answer the question below. As the world shifts toward renewable energy sources such as solar and wind power, the development of efficient energy storage technology has become increasingly critical. Because renewable sources are intermittent, generating electricity only when the sun shines or the wind blows, batteries are needed to store excess energy for use during periods of low generation. Lithium-ion batteries, widely used in everything from smartphones to electric vehicles, have become the dominant storage technology due to their high energy density and relatively long lifespan. However, researchers are actively exploring alternative battery chemistries, such as solid-state and sodium-ion batteries, which promise improved safety, lower costs, and reduced reliance on scarce materials like cobalt and lithium. Large-scale battery storage facilities are also being built alongside power grids to help balance supply and demand, reducing the need for fossil-fuel-based backup power plants. Continued advances in battery technology are widely seen as essential to achieving a fully renewable and reliable electricity grid. Question: What is the passage primarily about?

• A. The chemistry of lithium extraction
• B. The design of solar panels
• C. The role of battery technology in supporting the shift to renewable energy ✓
• D. The history of the electric vehicle