A Company Is Considering a Rate Change, Either an Increase

Multiple Choice

A company is considering a rate change, either an increase or a decrease in production, and
X_t = production in a time period
R_t = increase in production rate from Period t-1 to Period t
D_t = decrease in production rate from Period t-1 to Period t
Which of the following is correct?

A) X_t - X_{t - 1} = D_t - R_t
B) X_{t - 1} - X_t = D_t - R_t
C) X_{t - 1} - X_t = R_t -D_t
D) X_t - X_{t - 1} = R_t - D_t