求当前股票收盘价的2日算术平均价

A. ma2[2]:=(fc[1]+fc[2])/2; ma2[3]:=(fc[2]+fc[3])/2;ma2[4]:=(fc[3]+fc[4])/2;ma2[5]:=(fc[4]+fc[5])/2;ma2[6]:=(fc[5]+fc[6])/2;ma2[7]:=(fc[6]+fc[7])/2;ma2[8]:=(fc[7]+fc[8])/2;
B. fc:=close;for i=1 to datacount do ma2[i] : (fc[i-1]+fc[i])/2;
C. fc:=close;for i=2 to datacount do ma2[i] : (fc[i-1]+fc[i])/2;
D. fc:=close;for i=2 to datacount do ma2[i] : (fc[i-2]+fc[i])/2;