程序中有如下命令序列：
SELECT A
USE DEM01
SELECT B
USE DEM02
SET RELATION T0 RECN0()INTO A
SELECT C
USE DEM03
SET RELATION T0 RECNO()INTO B
SELECT B
G0 8
RECNO()，RECNO(1)，RECNO(3)
执行此程序段后，屏幕显示的结果是( )。

A．．
T．、．
T．、．
T．、．
T．
B．．F、．
T．、．
T．、．
T．
C．．
F．、．
T．、．
F．、．
T．
D．．
F．，．
F．，．
T．，．
T．

A．SUBSTR(XY,11,2)+SUBSTR(XY,1,8)+SUBSTR(XY,4)
B．SUBSTR(XY,15,4)+LEFT(XY,1,10)+RIGHT(XY,19)
C．SUBSTR(XY,15,4)+LEFT(XY,10)+RIGHT(XY,8)
D．SUBSTR(XY,15,4)+LEFT(XY,10)*RIGHT(XY,19,10)