Which one is NOT correct about an asynchronous communication in Java?

Question $5$ options:

We can use a callback function to achieve asynchronous communication in Java.

Compared to a syncronous communication, smaller number of tasks can be performed in a certain period of time.

It allows the program to perform other operations after starting a long running task.

Compared to a syncronous communication, It makes our program more responsive to the user's requests.