Swampy lands are most suitable for growing rice. This is because rice thrives in wetland environments where there is abundant water supply. Swampy lands usually have a high water table and can retain moisture for a long time, making them ideal for the cultivation of rice. Additionally, rice is a semi-aquatic crop that can tolerate flooding, making it well-suited for growing in areas with fluctuating water levels. Therefore, rice is the most suitable crop to grow in swampy lands.