Gary and Lisa are redecorating their home and are trying to decide how many gallons of paint to buy to paint the three bedrooms. What are some of the things they are probably using to help with the calculations?

A.  Ladder, calculator, and drop-cloth
B.  Cost of a gallon of paint and an estimate for how much paint is needed
C.  Software that helps calculate paint needed based on measurements of the room and advice from someone at the Do-It-Yourself store
D.  Work Packages and Resource Breakdown Structure

Thank you all.