在Visual Basic中，下列循环程序段输出“*”的个数最小的是（   ）

A：a = 5: b = 8  Do    Print "*"    a = a + 1  Loop While a < b

B：a = 5: b = 8  Do    Print "*"    a = a + 1  Loop Until a < b

C：a = 5: b = 8  Do Until a>b    Print "*"    b = b + 1  Loop  

D：a = 5: b = 8  Do Until a>b    Print "*"    a = a + 1  Loop