Ports, extremely expensive not only to develop, but also to maintain, earn revenues through fees payed by shipping companies exporting or importing goods through the port. Ports in countries that are completely self-reliant in terms of the manufacturing and production of commodities, raw materials and resources in general must generate lower incomes than ports of a similar size in countries that produce only a portion of their goods and resources since the latter are more likely to enjoy higher levels of activity than the former, and in turn, earn more income from fees being paid.

Which of the following, if true, casts the most doubt on the argument's conclusion?

Countries that enjoy high levels of production, whether industrial or agricultural, to the point that they become almost completely self-reliant, are always in a position of greater financial strength and stability than those that do not enjoy such abundant production.

Ports that choose to accommodate higher rates of exportation, as opposed importation, do not always do so because of a lack of a necessity for imported goods, but instead in some cases because of their proximity to sources of raw materials.

Because of the enormous expenses inherent to the successful operation of an active port, the accumulation of income from trade activity through the port is to continue for years before a port can begin to generate profits from its activity.

Ports that function as trading points for both importation and exportation acquire a reputation for being centers of financial activity and economical growth, thereby attracting the business of additional companies and the interest of investors.

Fees paid to a certain port by ships initiating the exportation of goods from that port, according to international shipping laws, must include a commission based on the profits earned by the retail of the wares carried by those ships.


The OA is E
I just did not understand this. Can some one pls explain?