As an employee of a short term insurer, you are keen to find out whether there is a market amongst your current household policyholders to add to all risk cover for cell phones which they have not insured under their policy with your company. You need to know how many of them have cell phones, how many are covered with you (and how many are uncovered). You figure out that you can obtain this information via contacting the clients using the policyholders data on file. You can telephone the clients, email them or post them a survey request.
Evaluate the listed methods of collecting the required data, briefly indicating the various considerations to be taken into account?