In this question, only one binary operation is given so it cannot be a Ring or Integral domain or field.For Ring or Integral domain or for field there must be Two binary operations are required and the algebraic structure looks like (S ,+ ,⨉) .
So ,option b ,c and d are False.
Now check the properties of groups.It satisfies all the conditions of groups.
Hence, it is a Group.
The correct answer is,(A) A Group