Statement 1 is correct. Monazite is a phosphate mineral that serves as a significant source of rare earth elements (REEs), such as cerium, lanthanum, and neodymium.
Statement 2 is correct. Monazite is a primary ore for thorium, a radioactive element with applications in advanced nuclear technologies.
Statement 3 is incorrect. Monazite deposits are not found across the entire Indian coastline. They are concentrated in specific heavy mineral sand deposits, particularly along the coasts of Kerala, Tamil Nadu, Odisha, and Andhra Pradesh.
Statement 4 is correct. The processing and export of monazite in India are regulated under the Atomic Energy Act. Only government bodies, such as Indian Rare Earths Limited (IREL) under the Department of Atomic Energy (DAE), are authorized to handle these activities.
Option (a) is incorrect because it includes Statement 3, which is factually inaccurate.
Option (c) is incorrect because it includes Statement 3, which is factually inaccurate, and excludes correct statements 1 and 2.
Option (d) is incorrect because it includes Statement 3, which is factually inaccurate.