C. They all emerged as a reaction to the harmful flaws of capitalism.
I'll offer one example as a case in point, that of Robert Owen as one of the "utopian" socialists. Robert Owen's vision reacted to the dehumanizing aspects of the Industrial Revolution by envisioning a socialist project in which all community members worked together in harmony. Owen was one of those called "utopian socialists" because they envisioned a society in which all persons participated together in building a common community. Owen was successful in turning around a gritty, grimy industrial town -- New Lanark, Scotland -- into such a community. However, when he tried to repeat such a community in America, at a place they called New Harmony, Indiana, the results were not so harmonious. Apparently having the negative factors of the Industrial Revolution to react against is what made Owen's socialist planning most attractive to people.
In a similar way, other forms of socialism, including the most expansive form of socialist thought in communism, were all reacting against the problems that arose due to the capitalist economies that arose out of the Industrial Revolution. Remember that the key work of Karl Marx and Friedrich Engels as founders of communism was titled, "Das Capital," and was a direct attack and critique on the capitalist system.