These laws reflected different views concerning wiretapping as
technology progresseD. The Federal Intelligence Surveillance Act
(FISA) of 1978 limited wiretapping for national security purposes as a
result of the record of the Nixon Administration in using illegal wiretaps.
The Electronic Communications Privacy Act (ECPA) of 1986
prohibited eavesdropping or the interception of message contents
without distinguishing between private or public systems. The Communications
Assistance for Law Enforcement Act (CALEA) of 1994
required all communications carriers to make wiretaps possible in
ways approved by the FBI.

It is important to note that mandatory controls are prohibitive (i.e., all that is not expressly permitted is forbidden), not permissive. Only within that context do discretionary controls operate, prohibiting still more access with the same exclusionary principle. In this type of control system decisions are based on privilege (clearance) of subject (user) and sensitivity (classification) of object (file). It requires labeling.

Explanation/Reference:
Explanation:
S-HTTP provides application layer security, while the other protocols provide transport layer security.
Incorrect Answers:
B: FTPS can use SSL.
FTPS (also known as FTPES, FTP-SSL and FTP Secure) is an extension to the commonly used File Transfer Protocol (FTP) that adds support for the Transport Layer Security (TLS) and the Secure Sockets Layer (SSL) cryptographic protocols.
C: SSL can be used by FTPS. SSL provides transport layer security.
D: SPX is a transport layer protocol (layer 4 of the OSI Model).
References:
Stewart, James M., Ed Tittel, and Mike Chapple, CISSP: Certified Information Systems Security Professional Study Guide, 5th Edition, Sybex, Indianapolis, 2011, p. 856

I think I am going to disagree with the original answer (B testing of the change) here. The question has REDUCES the assurance. "Personnel separate from the programmers should conduct this testing." -Ronald Krutz The CISSP PREP Guide (gold edition) pg 345