Question: Which of the following statements about the Java Memory Model (JMM) and thread synchronization is true?

A) The Java Memory Model guarantees that once a thread writes to a variable, any subsequent read of that variable by another thread will see the updated value immediately.
B) The volatile keyword ensures that a variable is stored in the CPU cache, providing faster access for threads.
C) Using synchronized methods or blocks guarantees that only one thread can execute the synchronized code at any given time, and it provides a memory visibility guarantee.
D) The Java Memory Model does not allow for any optimizations by the Java Virtual Machine (JVM) concerning the ordering of instructions in a multi-threaded environment.