Answer:
Options A, B and C are correct choices.
Step-by-step explanation:
Let c represent the cost of each shirt.
As Lorenzo bought 3 shirts, so the cost of 3 shirts will be 3c.
We have been given that the shirts are on sale for 20% off, so the total cost of three shirts after discount will be 3c minus 20% of 3c.
We can represent this information in an equation as:



Let us see our given choices one by one.
A. 0.80(3c)
Upon simplifying our given expression we will get,

Therefore, option A is a correct choice.
B. 3c−0.20(3c)
We have already seen that total cost of 3 shirts after discount will be 3c minus 20% of 3c and after simplifying our expression we will get,

Therefore, option B is a correct choice as well.
C. 3(c−0.20c)
Upon simplifying our given expression we will get,

Therefore, option C is a correct choice as well.
D. 1.20(3c)
Upon simplifying our given expression we will get,

Since total cost of 3 shirts after discount is 2.40c, therefore, option D is not a correct choice.