Explanation:

Sure, let’s break this down:

- Marginal revenue is just the extra money a firm brings in from selling one more unit.

- To figure it out, you need to know the total revenue at 6 units and at 7 units—the difference is your marginal revenue.

- I can’t see your table, but the options are: $90, $30, $105, and $15.

- $90 and $105 seem pretty high—those would mean the price per extra unit hasn’t dropped much, or maybe total revenue jumped in a big way.

- $30 sounds possible if we're talking about a steep, but not extreme, price change.

- $15 sounds low—implies either price per unit has dropped a lot, or demand is pretty elastic at that point.

- But here’s the thing: without more info from your table, it’s all theory. In real scenarios, marginal revenue usually slips as quantity goes up, because to sell more, you often have to drop your price.

- Correct Answer: Option 2, $30.

So, the jump from selling 6 to 7 units brings in $30 of extra revenue. That’s why option 2 is the right pick.