Both the american revolution of 1776 and the french revolution of 1789 were partially caused by
a) foreign armies invading
b) unfair taxes
c) the system of feudalism
d) governments persecuting religious leaders

It could be argued that both the American Revolution of 1776 and the French Revolution of 1789 were partially caused by "Unfair taxes," since both the French and British governments were taxing their people heavily and with no (or limited) representation.