Based on the additional information given by you, ProudPrivate, I've written to the US Embassy, requesting them for confirmation of the visa I can legally travel on for finishing my PPL requirements (carried forward from India). The only trouble is that I wrote to them three weeks ago and they haven't said anything till now.
If they don't respond by the end of the week I think I'll move forward with M1 processing, which will take some time to get done.