Answer: c)They are more expensive than potatoes without the vaccine.
A genetic engineering is a practice which is integral part of biotechnology which involves the genetic manipulation of organisms. In this the genome of organism is manipulated by incorporating the genome of the other organism, or some part of it is deleted so as to make organism resistance against diseases.
In the given situation, edible vaccines are incorporated in the potato plants, the vaccines are the chemical formulations which includes either the bacterial genome or some of it's agents which can fight against the one already present in the body causing diseases. This entire process requires an expensive technological support as a consequences of which the quality as well as price of these potatoes will be high as compared to conventionally produced potatoes.