What Was the Supreme Court's Rationale in the Civil Rights

What was the Supreme Court's rationale in the Civil Rights Cases (1883) for why Congress could not prohibit discrimination in public accommodations?

A) Congress cannot regulate public accommodations because they involve interstate commerce.
B) Congress can only regulate government discrimination, not discrimination by private individuals.
C) Congress cannot prohibit discrimination because doing so violates the First Amendment right to freedom of speech.
D) Congress cannot prohibit discrimination because there was insufficient evidence that discrimination exists.