Variability management is a major concern in successful exploitation of variabilities and commonalities of software product families which also affects different aspects of development activities. Modeling variabilities among products of a family is a key aspect of variability management discipline. To use software product line approach in information systems context, it is necessary to bring in variability in different phases of the life cycle, including business process modeling which is recognized as a key part of developing enterprise information systems. Consequently, modeling variability in business process models becomes an issue worthy of consideration. We use UML 2 activity diagrams to model business processes. Modeling solutions are proposed and classified based on the origins of variability at business process level. We have also studied the ways to avoid cluttering the model when including variability. An example case is utilized to clarify different aspects of our proposed method.