Which of the Following Is the Best Example of a Modified

Which of the following is the best example of a modified rebuy? 

A)  A contractor buying shingles from the same supplier for the roof of the fifteenth house he is building in Tara Woods.
B)  The production manager of a meat processing plant is buying a $90,000 high-tech meat slicing machine that will save the company an estimated $20,000 annually in wastage.
C)  A supermarket manager reordering 24 replacement plastic pallets for storing food.
D)  A company that manufactures computers switches to a new supplier that provides an improved version of microprocessor chips.