Read the following passage about renewable energy sources and mark the letter A, B, C, or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 18 to 22.

Renewable energy sources, once considered niche alternatives, are now becoming mainstream. Solar power, for instance, (18) _______ . Once dismissed as too expensive and inefficient, it is now recognized as one of the fastest-growing energy sources globally. Solar installations, (19) _______ , are being led by countries like China and the USA in terms of capacity. Another breakthrough was achieved when a village in India, which became one of the first entirely solar-powered communities in the region, successfully adopted solar technology.
The rise of renewable energy is driven not only by technological advancements but also by global efforts to reduce carbon emissions. (20) _______ . Governments, corporations, and individuals alike are investing in solar panels, wind turbines, and other clean energy technologies as part of a broader push toward sustainability.
Wind power is another key player in the renewable energy sector. (21) _______ . Wind turbines, which now dot landscapes worldwide, have become more efficient and cost-effective, generating power even in low-wind areas.
Using advanced battery technologies, (22) _______ . These systems ensure renewable energy is available at all times. Such advancements are crucial for maintaining a steady power supply, even when the sun isn't shining or the wind isn't blowing.