To solve this question, the user needs to know the correct idiom and its meaning. The phrase "get down to brass tacks" means to focus on the essential details or the main point of a matter.
Now, let's go through each option and explain why it is right or wrong:
A. silver: This option is incorrect because the correct idiom is "get down to brass tacks," not "silver tacks."
B. brass: This option is correct. The idiom is "get down to brass tacks," so option B is the correct answer.
C. copper: This option is incorrect because the correct idiom is "get down to brass tacks," not "copper tacks."
D. gold: This option is incorrect because the correct idiom is "get down to brass tacks," not "gold tacks."