Sig A: 4/5 - 600k, the smoke changing color feels very abrupt, especially on the left half of the sig would have liked a smoother transition there, also the left arm gets kind of blurry could be sharper; text is A+
Sig B: 5/5 - 750k, the best of the bunch great choice of background and the blending on the bottom of the render is great, might consider dropping the shadow on the text
Sig C: 3/5 - 450k, just feels a step down from the other two, would have liked to see the flames extend right to the edges