US army testing Android,iOS and Windows Phone to choose two of them

Perhaps everybody would agree with me on this point that currently the three most popular smartphone platform are iOS , Android and Windows Phone 7 and all of these have their own amazing distinct feature but definitely their are more iOS fans currently in the tech world.So, currently it has been reported that from last six or seven week US Army is testing all these three smartphone platform and whenever their testing phase is complete they will choose two of these smartphone platform whichever suits them best or I could say least favorable platform would be eliminated. 

Although this point seems little bit unusual that why they are choosing two of them as if they have to eliminate one why don’t they just stick with one.But the reason given for this is they want to keep the development cost as low as possible without cutting all the options.So , with two they can have a little choice.And perhaps when we have to choose two then I think iOS and Android have much better chance then Windows Phone 7.