Which ideology is the best?
"Social democracy is the idea that the state needs to provide security and equality for its people and should actively reorder society in a way that is conducive to such developments, but that such changes should be brought about gradually, legitimated by a democratically-elected majority. It is native to Europe, where social democrats regularly feature as one of the major parties and have led (or at least participated in) governments in most states at some point in time, most notably in Scandinavia (up to being nicknamed the "Nordic model", which is effectively a blend of social liberalism and social democracy). Social democrats typically regard government intervention as a force for good, constraining markets and engaging in redistributive efforts for the benefit of the lower classes in order to establish a more equitable society.
Somewhat confusingly, social democracy is not the same thing as democratic socialism, nearly-identical names notwithstanding. Modern social democrats believe in maintaining the capitalist system — democratic socialists do not (liberal socialists are the only socialists that do).
Just like socialism, the term is heavily misused by both supporters and opponents. Social democracy addresses the issues that in less interventionist forms of capitalism, wealth inequality is passed on amongst generations due to inequality of opportunity. Sectarian social democrats sometimes opposes democratic socialism due to fear that such system would turn authoritarian, however this is questionable as democratic socialism does not propose "democratic" centralism as authoritarian socialists like Lenin do. It tends to meet in the middle, due to its allowance of multi-party democracy and not investing too much economic power in the state."
Social Democracy (rationalwiki.org)