Fill in the blank with suitable prepositions.
My friend works _______ Samsung. She lives _______ Seoul.
The preposition ‘at’ is used while speaking about an organization. Since Samsung is an organization 'at' is the apt answer. Whereas ‘on’ is used to denote contact with a surface, while ‘of’ is used to show belonging or relation, which is not the case here. Therefore options B and D are incorrect. On the other hand ‘in’ is used to refer to cities. Since Seoul is a city ‘in’ is the apt answer. Therefore option C is correct while option A is incorrect.