Can you choose more than one option?
Because a conclusion should not repeat word-for-word the introducion (this would make it actually pretty redundant), but other than this, it should be all of the remaining! (but if i had to choose one, I'd go with "summarize the main points- this would be most effective and most relevant./)
So my answer is: it should restate the thesis AND summarize the main points AND be imaginative
but it should NOT repeat the introduction word-for-word.
Gold is a highly sought after dense, malleable, shiny, and soft precious metal that has been used as a form of currency for many centuries. It is the most valuable precious metal. It is aesthetically and intrinsically pleasing and has religious or symbolic meaning in many cultures.