Which of the Following Statements Are True Concerning Teachers' Rights

Which of the following statements are true concerning teachers' rights to free speech?

A) The Supreme Court has concluded that practical reality requires that government, at certain times and under certain conditions, be able to restrict employees' speech in order to fulfill its responsibilities to operate effectively and efficiently.
B) The Supreme Court has decided, however, that a public school teacher or other school employee may be restrained in the exercise of speech depending on whether it involves a matter of public concern or private concern.
C) While a public employee's speech is protected when speaking out on a matter of public concern, balancing the employee's and state's interests, the First Amendment does not protect a public employee's speech or expression concerning private or personal interest upon matters of public concern.
D) All are true
E) None are true