In the 1700s, an effect of the enlightenment was
1.a rise in support for representative government.
2.the creation of new protestant churches across europe.
3.an increase in new scientific discoveries and methods.
4.the return to classical ideas such as humanism and realism.

The correct answer is: "a rise in support for representative government."

The Enlightment philosophers, such as Locke, Monstequieu or Rosseau,  developed ideas that challenged, and ended up derrocating, the power structures of the Old Regime.

They promoted democratic principles, such as the definitions of bills of citizens' rights, social contract (citizens electing political representatives to create goverment through suffrage, in opposition to the prevailing absolute monarchies), and the division of the powers of the state in order to avoid excessive power accumulation in certain sectors, and risks of authoritarism.

All these ideas challenged the status quo, and gave rise to many revolutions in Europe, being the French Revolution the most remarkable one, and also has an effect overseas, as it influenced and triggered the American Revolution too.