was wondering which one is easiest and which one is hardest so i can plan my way. If more than 1 route is available, i will take the easiest route in terms of technical aspect

I would say in order of their height. Blanc, Elbrus and then Aconcagua.

Read some of the trip reports, that will give you a better idea. "Hard" means different things to different people.
Blanc can be done in 2-3 days (normally). Aconcagua and Elbrus take considerably more time and logistics.

pvnisher wrote: Blanc can be done in 2-3 days (normally).

Two days is possible indeed, but for 'normal' mountaineers that requires previous acclimatization. Of course, if you only plan two or three days for it you'll see that the weather decides to be uncooperative, whereas if you show up acclimatized and with a week to spare, you'll summit right away and wonder what all the fuss is about!

No objective dangers at all on either Aconcagua or Elbrus. That narrow ridge on the Gouter on Mont Blanc might make that a bit more dangerous, though.

mtnjim wrote:No objective dangers at all on either Aconcagua ...

When I was there, someone had to turn around and give up after being hit by rockfall in the Canaleta. For the most part, mtnjim is right, but you need to watch for idiots kicking down rocks from above.