1. What is vulnerability?

• A technique to breech the security of a network or information system in violation of security policy
• A documented body of evidence that provides a convincing and valid argument that a specified set of critical claims regarding a system's properties are adequately justified given application in a given environment
• A weakness in an organization or asset that could be exploited by an adversary
• A shortcoming or imperfection in software code, design, architecture, or deployment

I found in the CLE 81 slide pack a textbook definition of what is vulnerability... the answer given in the slide deck is bullet point 3 (in BOLD), verbatim. However when I took the test, this answer was wrong! I then retook the test and selected bullet point 4 (in italics and underlined), based on examples of vulnerabilities as defined the slide deck. This took was rejected as wrong. What am I missing here? Can you research this and give me some understanding on what I am missing?