Final answer:
The slope of a line in economics indicates the rate of change between two variables. In this case, it means for each additional unit of dried fruit, the cost increases by the same amount, representing a direct, positive relationship between quantity and cost.
Step-by-step explanation:
The slope of the line in an economic context typically represents the rate at which one variable changes relative to another. In this situation, where the slope of the line is described as the change in cost per unit of dried fruit, the correct interpretation would be option 2): The slope of the line is the change in cost per unit of dried fruit. This means that every unit of dried fruit costs the same amount. This implies a positive relationship between the amount of dried fruit and the total cost, where the cost increases by a constant amount for each additional unit of dried fruit purchased.
It's important to note that a positive slope signifies that as one variable (independent, usually represented by 'x') increases, the other variable (dependent, usually represented by 'y') also increases at a consistent rate. However, if the slope were negative, this would mean that an increase in the independent variable results in a decrease in the dependent variable. For instance, as the slope reflects the price of one good divided by another good, a negative slope would suggest an opportunity cost, where to gain more of one good, one must give up some amount of the other good.