@Nela I think you have the right "necessary" thinking but in this stimulus, we can't conclude that rocks are the only thing that could make this garden harmonious with nature. The stimulus doesn't say a garden needs to have rocks in order for the garden to achieve harmony with nature. Instead, it's imitation that is necessary to achieve harmony. So you have the right finding-what-is-necessary approach, and you know what part of the conclusion you need to prove, but you didn't pick the correct part of the argument

@JohnThorn same