下列数组声明正确的是( )。

A．n=5
Dim a(1 to n) As Integer

B．Dim a(10) As Integer
ReDim a(1 To 12)

C．Dim a() As Single
ReDim a(3,4) As Integer
ReDim a(1 to n)As Integer

D．Dim a() As Integer
n=5