Workflow nets are a class of Petri nets for the analysis of business processes. A Workflow net has a unique source and a unique sink place and all places and transitions are on a directed path from this source place to this sink place. A Workflow net is sound if and only if: a) from every reachable marking a marking can be reached that marks the sink place (option to complete), b) every reachable marking that marks the sink place marks it with one token only and marks no other place (proper completion), and c) for every transition a marking can be reached that enables this transition (no dead transitions).

1. Create a Workflow net that only violates the option to complete property.

2. Create a Workflow net that only violates the proper completion property.

3. Create a Workflow net that only violates the no dead transitions property.

4. Create a Workflow net that violates the option to complete and proper completion properties, but not the no dead transitions property. Explain your answers. Hint: You may want to construct the reachability/coverability graphs of the proposed Workflow nets to verify your answer.