which thumbnail would be the most aesthetically pleasing or suitable for a tutorial?

C or D (if you remove gradient). Other examples have issues with composition and paddings. In addition Substance Painter icon has long been updated.

tuturial ( i see how many others vote see repsonse ) i defo take view into account

long version ( ai voice is bit annoying )
https://www.youtube.com/watch?v=h6D32M3ewDw&t=2s

speed run ( i know some dont like speed runs )
https://www.youtube.com/watch?v=3J2ZY7GRzeI

tuturial ( i see how many others vote see repsonse ) i defo take view into account

long version ( ai voice is bit annoying )
https://www.youtube.com/watch?v=h6D32M3ewDw&t=2s

speed run ( i know some dont like speed runs )
https://www.youtube.com/watch?v=3J2ZY7GRzeI

tuturial ( i see how many others vote see repsonse ) i defo take view into account

long version ( ai voice is bit annoying )
https://www.youtube.com/watch?v=h6D32M3ewDw&t=2s

speed run ( i know some dont like speed runs )
https://www.youtube.com/watch?v=3J2ZY7GRzeI

double post apoligies jaguar) lag on my broswer mate)

ive aligned it now based on smallest text ( im new to baseline grid ) ive used my smallest type as basline grid ... which is font size 36 ,, largest font 72 ... , i jsut couldnt find my line heigh for my arial font , is used 36 poitn see in the corrner as baseline grid

i not sure on these rules ??? just seeing these rules now .. i was trying to make the paddng bettter

ive tried to align it better
https://ibb.co/cXRscXB

ive aligned it now based on smallest text ( im new to baseline grid ) ive used my smallest type as basline grid ... which is font size 36 ,, largest font 72 ... , i jsut couldnt find my line heigh for my arial font , is used 36 poitn see in the corrner as baseline grid

i not sure on these rules ??? just seeing these rules now .. i was trying to make the paddng bettter

ive tried to align it better
https://ibb.co/cXRscXB

cheers jags

All are fine, but I think image B (https://ibb.co/Zd7vs9N) definitely edges it for me personally! Nice work!