Mumbai, Nov 14 (UNI) Dissident trustees Venu Srinivasan and Vijay Singh have questioned the positions taken by former trustee and Tata Trusts Chairman Noel Tata''s supporter Darius Khambata, regarding the stock exchange listing of group holding company Tata Sons as well as the reappointment of N Chandrasekharan as Chairman of Tata Sons.