The correct answer is: B. in a simple and brief manner.
The phrase “to tell you in a nutshell” means to give a brief summary of something. In this case, the speaker is saying that they will give a brief summary of how lust for power and money has almost spoiled the person they are talking about.
Option A, “as objectively as possible,” is not the correct answer because the speaker is not trying to be objective. They are giving their own opinion about how lust for power and money has affected the person they are talking about.
Option C, “an actual experience described vividly,” is not the correct answer because the speaker is not describing an actual experience. They are giving their own opinion about how lust for power and money has affected the person they are talking about.
Option D, “to take in confidence,” is not the correct answer because the speaker is not asking the listener to take anything in confidence. They are simply giving a brief summary of how lust for power and money has almost spoiled the person they are talking about.