Answer :
These marks tell scientist that these areas were once much colder than they are today.
Option: C
Explanation:
Climate has changed in large scale through out the geolological history. Once all the continents were grouped together according to the continental drift theory. Thereafter with the effect of gravitational force and tidal force all continents divided and moved towards equator wards and west wards in definite directions.
So the present climatic condition what we see now in different continent is not their actual characteristics from beginning. Therefore South America, South Africa, India and Australia all these countries were under severe cold climate once that's why they have glacial striation.