ANSWER
C = 12p + 3
Step-by-step explanation
We want to find the equation that represents the cost of having a number of pizzas delivered.
The pizzeria charges $12 per pizza. This means that for p pizzas, the charges will be:
Charges = 12 * p
Charges = 12p
The total cost is the sum of the pizza charges and the delivery charges. That is:

That is the equation.