Answer:
Option C
Step-by-step explanation:
Originally, it only referred to white men. Most if not all people of color were slaves, and women were considered inferior. (look up "racism and sexism in the history of the US") Now, although white men arguably have "more rights" (sexism and racism are still very much alive today), the phrase is meant to include all people, at least all citizens of the United States.
A. This is wrong, because "all men are created equal" was part of the US Declaration of Independence, and therefore shouldn't be referring to Brits.
B. This is wrong, because originally it didn't refer to men of color.
D. This is wrong, because the phrase was meant to convey that all people (all white men) should be considered equal regardless of status, education, etc.