Sentence Correction

Though formerly considered ill-formed and primitive, Henri Rousseau has become an iconic figure of Post-Impressionism for his dream-like canvases painted like he was naive.

a) Henri Rousseau has become an iconic figure of Post-Impressionism for his dream-like canvases painted like he was naive.
b) Henri Rousseau's canvases, painted in a naive, dream-like style, later established the artist as an icon of Post-Impressionism.
c) Henri Rousseau painted canvases in a naive, dream-like style that has become an icon of Post-Impressionism.
d) Henri Rousseau's canvases were painted in a naive, dream-like style that was later iconic of Post-Impressionism.
e) the canvases of Henri Rousseau are icons of Post-Impressionism due to being painted in a naive, dream-like style.

I have chosen answer c) that is not the correct answer because of the following explanation "(C) This choice incorrectly places Henri Rousseau (instead of his paintings) as the subject of the opening modifier "though considered aesthetically primitive . . ." Additionally, the phrase "style that has become an icon of Post-Impressionism" is incorrect. Rousseau, not his style, later became an icon."

Even though I have understood the reasons of my failure, I do not understand why the answer choice b) is correct. Into my studying material I have seen a rule that states "an introductory modifying phrase must modify the subject of the sentence" and then a corollary saying that "an introductory modifying phrase cannot modify a noun in the possessive (-'s) form."

Ron, could you help me to tackle this issue?

Thanks.