Final answer:
The correct equation representing the relationship between the number of T-shirts, the number of colors, and the total cost is 'Total Cost = Number of T-shirts × Number of Colors'.
Step-by-step explanation:
To ascertain the correct equation for the relationship between the number of T-shirts ordered, the number of colors, and the total cost, we need to analyze the variables involved. The total cost usually increases with both the number of T-shirts and the number of colors used in the printing process. Therefore, the most plausible choice among the given options would be that the total cost is proportional to the number of T-shirts and the number of colors. This leads us to an equation of the form: Total Cost = Number of T-shirts × Number of Colors. This equation represents a direct relationship where, if either the number of T-shirts or the number of colors increases, the total cost will also increase accordingly. Option (a) is the relevant equation for such a scenario.