Statement (1) is insufficient. We don't know how many of the stocks are domestic. Statement (2) has a similar problem: We don't know how many of the domestic securites are stocks.

Taken together, we still can't answer the question. It's possible that there are 28 domestic stocks--perhaps all of the stocks are domestic. It's also possible that there are as few as 23 domestic stocks--that is the minimum overlap of stocks and domestic securities. Choice (E) is correct.