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The example in the image may not be the best of examples. It’s a nested quote created by four people quoting a post (one quotes, another quotes the quote, another quotes the quote of the quote, and so forth). Generally speaking, in order to respond, you are not going to need to reference the complete nested quote.
It’s best to try to delimit the quote to the part that is relevant, and not to drag along massive chunks of (possibly nested) quotes.
In general, if you want to answer to multiple people you’d make a single quote from each post you want to answer to, and delimit the relevant part (or leave a general quote as I did above so it’s clear that I’m responding to your post).