The correct answer is (a) Indo-Gangetic Plain.
The Indo-Gangetic Plain is a vast, fertile plain in the northern part of the Indian subcontinent. It is formed by the confluence of the Indus and Ganges rivers, and is home to over half of India’s population. The plain is known for its rich agricultural land, and is a major producer of wheat, rice, and other crops.
The Deccan Plateau is a large, elevated plateau in the southern part of the Indian subcontinent. It is composed of ancient rocks, and is relatively dry and sparsely populated.
The Thar Desert is a large, arid desert in the northwestern part of India. It is one of the hottest and driest places on Earth, and is home to a variety of desert plants and animals.
The Coastal Plains are a narrow strip of land along the eastern and western coasts of India. They are composed of alluvial soil, and are home to a variety of coastal vegetation and wildlife.