Companies Vary as to the Amount of Security They Require

Companies vary as to the amount of security they require or can afford for their computer files.A company that sells a complete line of firewalls from a no-frills version to a version that uses retinal scans for admittance would employ which promotional element to most effectively promote its product to businesses?

A) advertising
B) sales promotion
C) public relations
D) personal selling
E) expert endorsements