Which of the Following Is Included in Gross Private Domestic

Which of the following is included in gross private domestic investment?
I. Macy's purchase of new computerized cash registers
II. repairs to and replacements to the carpeting at Macy's
III. your purchase of a new queen-sized mattress from Macy's
IV. changes in Macy's business inventories

A) I only
B) I and II only
C) I, II, and IV only
D) I, II, III, and IV