单项选择题

Visual FoxPro中,下列程序段执行以后,内存变量X和Y的值是 CLEAR STORE 3 TO X STORE 5 TO Y SET UDFPARMS TO REFERENCE DO PLUS WITH (X),Y X,Y PROCEDURE PLUS PARAMETERS A1,A2 A1=A1+A2 A2=A1+A2 ENDPROC

A.3 13
B.8 21
C.8 13
D.13 21