Confused About One of the Atlassian ACP-120 Questions

[Harold Grace]

I am currently preparing for the Atlassian ACP-120 exam and came across a question that I'm not completely sure about. I'd appreciate it if someone could explain the correct answer and the reasoning behind it.
Question:
[Workflows and Automation]
An automation rule should send an email with the issue key in the subject line. Identify the
correct syntax to use in the Send Email action.

Options:
A- {{triggerIssue.issuekey}}
B- {{issue.key}}
C- {{issueKey}}
D- {issue.issuekey}
E- issue.key

I would also like to understand why that option is the right answer so I can better understand the concept.

[Dev]

The correct answer is B. In Jira Automation, issue.key is the standard smart value used to reference the current issue's key. When used in an automation rule, it should be written as double curly braces around issue.key.

[Brain Lee]

The correct answer is B. {{issue.key}}. {{issue.key}} is the correct syntax because Atlassian Automation uses smart values to insert dynamic issue data into actions such as Send Email. The {{issue.key}} smart value automatically retrieves the key of the current issue (for example, PROJ-123) and inserts it into the email subject when the automation rule runs.
While preparing for the ACP-120 exam, I found that practicing these types of automation questions really helps reinforce the concepts. If you're looking for additional practice, the ACP-120 practice questions from P2PExams are a useful resource for getting familiar with similar exam-style scenarios and understanding why the correct answers work.