The University of Sydney Page 193. Which of the following is the most serious software threat?1. Identity theft2. An unapproved routine has been inserted in the software3. The program is not thoroughly tested4. The software is difficult to use–Identity theftis a security threat but we cannot say that is purely a software threat.–Difficulty in usage and slowness are usability issues–If software is not thoroughlytested it may lead to unidentified vulnerabilities in the software. However, insufficient testing is not a software threat.–In contrast, an unapproved routine inserted in the software is clearly a software threat.