Question: What is the effect of the synchronized keyword in Java when used with a method?

A) It ensures that only one thread at a time can execute the synchronized method on the same object instance, thus providing mutual exclusion.
B) It automatically increases the priority of the thread executing the synchronized method, making it execute faster.
C) It allows the synchronized method to execute concurrently with other synchronized methods in different objects.
D) It makes the method accessible only to subclasses, restricting access to other classes.