[Tango-L] What is tango?

[Tango Society of Central Illinois]

Is this tango?

[A]  http://www.youtube.com/watch?v=iqeIbOgvdtc

How about this?

[B]  http://www.youtube.com/watch?v=qhxZoV3t61c

- from approx 3:00 - 6:00 (ignore commentary)

Is this tango?

[C]  http://www.youtube.com/watch?v=T-T6OiM7pSY&feature=related

and finally this?

[D] http://www.youtube.com/watch?v=yuIIj4HiAh0

They are all called 'tango'.

Is this confusing or not?

Ron