What is the correct syntax to define a custom VBA function that takes two arguments and returns a value?

O a$.$ Declare MyFunction$($arg$1$ As DataType, arg$2$ As DataType$)$ As DataTypeStart MyFunction$($arg$1$ As DataType, arg$2$ As DataType$)$ As DataType

O b$.$

O c$.$

Function MyFunction$($arg$1,$ arg$2)$

O d$.$Sub MyFunction$($arg$1,$ arg$2)$