Consider the following statements of Kupier (1949, 1951) and choose the correct answer:
1. A part of a huge cloud of dust and gas condensed to form primarily a proto-sun of low density surrounded by a rotating cloud disk
2. The proto-earth probably was a low-temperature body of gases and solids of about 500 times the earth's present mass
3. The accumulation of cold solid, the planetesimals, is the main process in the formation of primitive earth
4. The size of the planetesimals ranged in between the size of asteroids and that of dust particles

A. Only 2, 3 and 4 are true

B. Only 1, 3 and 4 are true

C. Only 3 and 4 are true

D. Only 1 and 2 are true

Answer: Option D