What is the possible explanation for this?

Administrator Dave logs into R80 Management Server to review and makes some rule changes. He notices that there is a padlock sign next to the DNS rule in the Rule Base.

What is the possible explanation for this?
A . DNS Rule is using one of the new feature of R80 where an administrator can mark a rule with the padlock icon to let other administrators know it is important.
B. Another administrator is logged into the Management and currently editing the DNS Rule.
C. DNS Rule is a placeholder rule for a rule that existed in the past but was deleted.
D. This is normal behavior in R80 when there are duplicate rules in the Rule Base.

Answer: B