All those who have been in contact with the patients with influenza A have been isolated, and all those who have been isolated have been in contact with Xiao Wang. If the above proposition is true, which of the following is also true? ['Xiao Wang is a flu patient.', 'Xiao Wang is not a non-A flu patient.', 'Someone may not have had contact with a person with influenza A. but had contacted Xiao Wang.', 'All patients with influenza A have contacted Xiao Wang.']