The question specifies that the vulnerabilities are application threats.

SQL injection and buffer overflow are both classic examples of application-layer attacks that target flaws in code and software design.

SQL Injection: Exploits improper input validation in database queries, allowing attackers to execute malicious SQL statements.

Buffer Overflow: Occurs when a program writes more data into a buffer than it can handle, leading to memory corruption and potential remote code execution.

Why the Other Options Are Incorrect:

B. Man-in-the-middle and physical security attack: MITM is a network attack, and physical attacks are not application-based.

C. DNS and ARP poisoning: These are network-level attacks, not application-level.

D. Footprinting and spoofing: Both are reconnaissance or identity-deception techniques, not application-layer threats.

Conclusion:

Bob identified application threats, namely SQL Injection and Buffer Overflow attacks.

Final Answer: A. SQL injection and buffer overflow attack

Explanation Reference (Based on CTIA Study Concepts):

CTIA categorizes SQL injection and buffer overflow as application-level vulnerabilities exploited through improper input handling and insecure coding.