Welcome to the Tridion Community and asking a clean question.
To get this information you may try the following Event System code block below:
private static void WorkflowEvent(ActivityInstance activityInstance, FinishActivityEventArgs args, EventPhases phase)
{
IEnumerable<WorkItem> workItems = activityInstance.WorkItems;
WorkItem currentWFItem;
using (IEnumerator<WorkItem> iter = workItems.GetEnumerator())
{
iter.MoveNext();
currentWFItem = iter.Current;
}
if (currentWFItem != null)
{
Component currentComponent = (Component)currentWFItem.Session.GetObject(currentWFItem.Subject.Id);
ApprovalStatus approvalStatus = currentComponent.ApprovalStatus;
}
}