If 3 pencils cost $1.50, how much do 12 pencils cost?

To determine the cost of 12 pencils based on the information given, we first need to calculate the cost of one pencil. The cost of 3 pencils is $1.50, so we can find the cost per pencil by dividing the total cost by the number of pencils.

Dividing $1.50 by 3 gives us $0.50 as the cost for one pencil. Now, to find out how much 12 pencils will cost, we multiply the cost of one pencil by 12.

So, we take $0.50 and multiply it by 12:

$$0.50 \times 12 = 6.00.$$

This indicates that the cost for 12 pencils is $6.00. This calculation shows that the correct choice reflects a straightforward scaling of the original cost based on the number of pencils involved, confirming that $6.00 is indeed the right answer.