Explanation/Reference:
Explanation:
A public posting on the internet is not secure. Compared to the internet, an intranet provides more control.
Incorrect Answers:
A: A private posting provides high security and control.
B: Ethernet is a link layer protocol in the TCP/IP stack. An Intranet is defined on the physical layer. The data link layer provides more control compared to the physical layer.
D: An extranet is a website that allows controlled access to partners, vendors and suppliers or an authorized set of customers - normally to a subset of the information accessible from an organization's intranet. As an extranet is a subset of an intranet is provides more security and control.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 661

The correct answer is C. 40% to 60% relative humidity is recommended
for safe computer operations. Too low humidity can create
static discharge problems, and too high humidity can create condensation and electrical contact problems.

Explanation/Reference:
Explanation:
ICMP and IGMP work at the network layer of the OSI model.
Incorrect Answers:
A: There is no Datagram Layer in the OSI model.
C: ICMP and IGMP do not belong to the Transport layer of the OSI model. TCP and UDP are examples of protocols working at the transport layer.
D: ICMP and IGMP do not belong to the Transport layer of the OSI model. ARP, OSOF, and MAC are examples of protocols workings at the data link layer.
References:
https://en.wikipedia.org/wiki/Network_layer

IP is a datagram based technology.
DIFFERENCE BETWEEN PACKETS AND DATAGRAM
As specified at: http://en.wikipedia.org/wiki/Packet_(information_technology)
In general, the term packet applies to any message formatted as a packet, while the term
datagram is generally reserved for packets of an "unreliable" service.
A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not
notify the user if delivery fails. For example, IP provides an unreliable service.
Together, TCP and IP provide a reliable service, whereas UDP and IP provide an unreliable one.
All these protocols use packets, but UDP packets are generally called datagrams.
If a network does not guarantee packet delivery, then it becomes the host's responsibility to
provide reliability by detecting and retransmitting lost packets. Subsequent experience on the
ARPANET indicated that the network itself could not reliably detect all packet delivery failures, and
this pushed responsibility for error detection onto the sending host in any case. This led to the
development of the end-to-end principle, which is one of the Internet's fundamental design
assumptions.
The following answers are incorrect:
IP segment. Is incorrect because IP segment is a detractor, the correct terminology is TCP
segment. IP is a datagram based technology.
IP frame. Is incorrect because IP frame is a detractor, the correct terminology is Ethernet frame. IP
is a datagram based technology.
IP fragment. Is incorrect because IP fragment is a detractor.
References:
Wikipedia http://en.wikipedia.org/wiki/Internet_Protocol