(1) i have a limited interest in people whose main topic of conversation is themselves and who never show any interest in what is happening to me. (2) group i avoid is people who never allow facts to interfere with their opinions. a. another b. also c. one d. then

Okay, The best way to figure is by reading the sentence aloud with a choice.

So when you put then in the blank space and you read the sentence out loud, it does not make sense. It sound weird. So you can rule D. out.

C. Okay, this is a trick answer. The fact that sentence 1 brings up a group before sentence 2, it rules out C.

B. Is also weird sounding in this sentence. Read the sentence out load with the word filling the blank. Trust me it will help narrow down your choices! 

A. Is you answer!! The transition between each the sentences with another makes sense!

Does that help?