Of the four choices, magnetic media is the
most sensitive to damage from heat, smoke, water, and humidity.

The System Owner is responsible for ensuring that the security
plan is prepared and for implementing the plan and monitoring its
effectiveness. The System Owner is responsible for defining the system's operating parameters, authorized functions, and security requirements. The information owner for information stored within,
processed by, or transmitted by a system may or may not be the same
as the System Owner. Also, a single system may utilize information
from multiple Information Owners.
The Information Owner is responsible for establishing the rules for
appropriate use and protection of the subject data/information (rules of behavior). The Information Owner retains that responsibility even when the data/information are shared with other organizations.
Source: NIST Special Publication 800-18, Guide for Developing Security
Plans for Information Technology Systems.

According to static's, this is the greatest cause, Electrical distribution systems, specially those not installed through standards are very prone to fail and make fire inside places. AC equipment its not very prone to make fire. Natural causes it's a possibility but is definitively not the most prevalent cause. Heating systems are a very rare case of Fire beginners.

Since fiber optics does not use electrical signals to transmit the information (it uses lights that goes through the mirrored silvered cable from source to end), its not affected by EMI (Electro Magnetic Interference) like other copper transmission methods like 10base5 and 10base2, therefore EMI does not affect the possible transmission distance. Fiber optics can have a great distance between end points, much greater than the copper transmission methods. Examples of Fiber optics standards are: 100BaseFX and 1000BaseFX.

HTTP is Port 80.
Reference: MAIWALD, Eric, Network Security: A Beginner's Guide, McGraw-Hill/Osborne Media,
2001, page 135.