Which prog. laungauge is basics of all laungauge.

Answer 1

It's your choice. If easier syntax is what you crave then go with Ruby or python. If you plan to start solely on SoloLearn then I recommend to go with Ruby. You can start with the evergreen C too, though the course is unavailable here.
C is quite vintage. This could be said as the basis on what other languages are build upon.

Answer 2

assembly is, but if you need more deep, go for machine language

Answer 3

yes c is basic ....

Answer 4

c

Answer 5

BPL
Even C is derived from BPL

Answer 6

Additional detail of C
C compiler is also a C program