The question asks us to choose the statement that, if true, would add the least depth to the author's prediction about start-ups. That is, we need to choose the option which goes against the author's prediction.

What is the author’s prediction about start-ups offering few product options? He predicts that these start-ups would be forced to offer variety due to the steep growth expectations of investors. That is, profit motive drives the push towards new product options. If start-ups are able to meet the desired profit goals without expanding their product range, then the author's prediction is no longer valid. So, option 1 is a possible answer choice.

Consider option 2. If the government doubles tax for these start-ups, the pressure on them to make a profit increases. This actually supports the author's prediction. So, it is ruled out.

If option 3 is true, that is, if regular customers of these start-ups lose trust in them, sales will decline and hence there would be more pressure on them to expand their range to make profit. This option too supports the author's prediction.

That start-ups with few product options are 'still just working within a consumer market that’s broken in systemic ways' is an argument used by the author to make his point about the narrowness of choice for certain consumer segments. This does not in any way go against the author's prediction about these start-ups being forced to expand their product range.

So, the option that adds least depth—goes against—the author's prediction is option 1.