Which of the following is true of the C# async keyword?A ) It is required on any method using the await keyword.B ) All of these answers are correctC ) It is required on any method utilizing the Parallel namespace.D ) It causes the method to spin off a separate thread.E ) Async methods must have a return type of Task or void.

The correct answer is B) All of these answers are correct.

Here's why:

A) It is required on any method using the await keyword. This is true because the await operator can only be used in an async method.

C) It is required on any method utilizing the Parallel namespace. This is true because the Parallel class provides support for parallel loops and regions, which are often used in async methods.

D) It causes the method to spin off a separate thread. This is true because the async keyword enables you to write asynchronous code that looks like synchronous code.

E) Async methods must have a return type of Task or void. This is true because an async method with a void return type can't be awaited, and the caller of a void-returning method can't catch any exceptions that the method throws.