Difference between MustInherit and Abstract Class

Question

Could someone please explain to me the differences between an abstract class and a class marked MustInherit?

Both can implement shared and instance constructors and logic. Both can/must be inherited.

So why use one over the other and what is the difference?

Answer 1

MustInherit is to VB.NET as abstract is to C#

Answer 2

MustInherit is VB.NET and abstract is c# - they are modifiers that declare the same thing.

abstract (C# Reference)

MustInherit (Visual Basic)