Consider the following definition of an atomic test-and-set operation and assume it is available in the assembly-language instruction set for xv6. Note that "test-and-set" is not a very precise name for this primitive; a better name would be "set and return prior value". // Note I have to use # instead of to indicate dereferencing, because Gradescope parses the as a formatting indicator boolean TestAndSet(boolean_ref &lock) { boolean initial = #lock; // get current value #lock = true; // set value to true return initial; // return the value we read, for caller to test } Now consider this implementation of a spinlock in xv6: void acquire(struct spinlock *Ik) { pushcli(): if(holding (Ik)) panic("acquire"); while(TestAndSet(&lk->locked) != 0) ; _sync synchronize(): } Which of these statements is true? O This implementation is correct O The while loop is not needed The while should be testing "!= 1", instead of "!=0" The sync synchronize() is not needed