I should have mentioned that if you want to do it similar to your code,
just adjust vector B like this...

Sub Demo()
Dim A As Variant
Dim B(1 To 4, 1 To 1)
Dim C As Variant

A = [{2,2,1,3;1,3,4,4;5,4,1,5;5,4,3,4}]

B(1, 1) = 5
B(2, 1) = 4
B(3, 1) = 3
B(4, 1) = 2

With WorksheetFunction
If Abs(.MDeterm(A)) < 0.0000000001 Then
MsgBox "A is Singular"
Exit Sub
End If

C = .MInverse(A)
C = .MMult(C, B)
End With
End Sub

= = =
HTH :)
Dana DeLouis