You can really use either one you wish. The meanings are the same. 'Operation' is an uncountable noun for the process; 'operations' is the plural countable noun for the various manifestations of 'operation'.
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When we talk about Business - it should be 'Operations' because any business is combination of various activities associated in that particular business and nothing in a business can be done in isolation from its' related activities. Operation literally means process and Business is always a combination of interrelated processes and therefore, business operations.