UPSC Civil Services Model Paper 4

Glacial movements erode a very large portion of the earth and deposit them slowly over a place where other forces of nature act on it to form soil. So, 1 contributes.
Magma is responsible for the formation of lava and its cooling forms igneous soil. So, 2 contributes.
Groundwater does not form soil as such but it can cause salination of soil if is withdrawn excessively. In areas of limestone, it forms landforms, but not soil. So, 3 does NOT contribute.