Complex sentence: In Canada, CST sells Ultramar fuels through 848 retail sites in Quebec, the Atlantic provinces and eastern Ontario and is one of the largest retail distributors of home heating oil in Eastern Canada.
Split into simpler sentences: In Canada, CST sells Ultramar fuels through over 840 retail sites in Quebec, the Atlantic provinces and eastern Ontario. Additionally, the company is one of the largest retail distributors of home heating oil in Eastern Canada.