Final answer:
The total population of Pierce City is calculated by dividing the number of people under the age of 20 (751) by 12%, which gives a total population of 6258, making the correct answer C) 6258.
Step-by-step explanation:
To find the total population of Pierce City, we can use the fact that the 751 people under the age of 20 represent 12% of the total population. To do this, we need to divide the number of people under the age of 20 by the percentage they represent in decimal form:
Total Population = Number of people under 20 / Percentage of total population
Total Population = 751 / 0.12
Total Population = 6258.33, which we round down to 6258 since we cannot have a fraction of a person.
Therefore, the correct answer is C) 6258.