The correct answer is (a) Amarkantak in Shahdol district.
The Son River is a major river in central India. It is a tributary of the Ganges River. The Son River originates in the Amarkantak hills in the Shahdol district of Madhya Pradesh. The river flows through the states of Madhya Pradesh, Chhattisgarh, Jharkhand, and Bihar. The Son River joins the Ganges River near Patna, Bihar.
The Son River is a major source of irrigation for the region. The river is also a popular destination for fishing and boating.
The Son River is a vital part of the ecosystem of central India. The river provides habitat for a variety of plants and animals. The river is also a source of drinking water for millions of people.
The Son River is a beautiful and important river. It is a source of life for the people and animals of central India.
The other options are incorrect because they are not the actual source of the Son River.
(b) Son Muda in Shahdol district is a tributary of the Son River.
(c) Son Bachharwar in Bilaspur district is a tributary of the Son River.
(d) Mandla plateau is a plateau in Madhya Pradesh. The Son River does not originate from the Mandla plateau.