23. (2 points) For a moving-average process of order q, i.e. rt=c0+at+1at1++qatq : which of the following is NOT correct? A. {at}t=1T is a white noise process B. c0 is also the constant mean of the time series {rt}t=1T C. the multistep-ahead forecasting error becomes c0 after the first q steps D. the lagged values of white noise process {at}t=1T will contribute to the forecasted value within q steps 24. (2 points) For an AR(1) process {rt}t=1T, i.e. rt=0.50.2rt1+at, where at is current-period white noise. What is the value of autocorrelation function (ACF) when lag number =3 ? A. -0.008 B. -0.04 C. 0.001 D. -0.125 25. (2 points) For a process {rt}t=1T which satisfies rt=0.5+rt1+at, where at is currentperiod white noise, which of the following is NOT correct? A. as time t increases by one unit, rt on average increases by 0.5 B. rt does not have finite mean or finite variance C. the first-order difference rt=rtrt1 has finite mean and variance over time D. {rt}t=1T has unit-root and is stationary process