C# sealed vs Java final

Question

Would anybody please tell me as the reason the following use of sealed does not compile? Whereas, if I replace sealed with final and c

Answer 1

Tigran's answer is not wrong while Joey's is a little incorrect.
Firstly you can look into this page: What is the equivalent of Java's final in C#?.
the sealed key word can apply to class,instance method and property but not variables, or interface's methods. Classes with sealed cannot be inherited. When sealed put on method， it must be by override in company. Every struct is sealed, so struct cannot be inherited. Check this image: