The correct answer is - D. All of the above.
If the trend of unsustainable fishing continues, than the fish that is caught on regular basis will lose to many individuals, disrupting the reproduction cycle as well, and very soon their number will be very low. Once that happens, they will become less available on the market.
If only one species is starting to disappear from the ecosystem, it can disrupt big portion of that ecosystem, but when there's multiple species rapidly declining in numbers, than it is a catastrophe and it affects the whole ecosystem in a negative manner.
Once the fish is scarce, and very limited on the market, its price will sky-rocket, thus making it unavailable for most of the people. And not only that, but lot of other marine animals that have been affected by the decline in the fish's populations, will also become scarce, and their prices will become much bigger as well, thus having a chain reaction.
