The following information is available for the year ended December 31:

Beginning raw materials inventory $3,000
Raw materials purchases 4,200
Ending raw materials inventory 2,700
Office supply expense 1,600

The amount of raw materials used in production for the year is:

A. $4,500.
B. $1,500.
C. $7,200.
D. $2,900.
E. $4,000