Which scenario is an example of extrinsic

Extrinsic motivation is driven  by external factors , which will make people  do things to gain external benefits. Thus, the scenario that exemplifies extrinsic motivation is the fact that Lacey ran into a heated shop to warm up, when the temperature suddenly dropped. What made Lacey react in that way so that he could take shelter from the weather ? An external factor: extremely cold temperature.  The other examples stand for intrinsic motivation since the drive that activates a certain behaviour in those people comes from within their own selves:  not feeling like answering the door; feeling guilty and confessing ; and loving animals and volunteering for rescuing them.  

the answer is decimated

quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.

the topic sentence in this paragraph is:

topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.

which incidentally tells you what a topic sentence should be.