Correct Answer :
B. their holding dogmas that are different from our own
Dogmatic is used to describe someone who has an arrogant attitude based on unproved theories. For example, if you dogmatically try to prove that the world will end in 2014, you will just be considered funny. The statement is about what really makes us say that someone else is dogmatic. Option (b) is correct, because dogmas are a set of beliefs that one has and is pretty firm about them, so when we meet people who go against our ideas, and hold fast to their own, we term them as dogmatic. For example, a non-religious person could say that a religious person is dogmatic. Option (a) is clearly wrong. Option (c) is wrong, because extremism refers to any political theory which favours immoderate uncompromising policies, so it is clearly out of the context. Option (d) is wrong, because it doesnt refer to the point in question. It simply repeats the meaning of being dogmatic.