Which statement is true about rule shadowing?

Question $36$Answer

a$.$

Rule shadowing cannot be used in Palo Alto Networks Firewalls.

b$.$

Since rules are processed in bottom top order, a rule can be hidden $($not evaluated$)$ if a lower order rule overshadows it$.$

c$.$

Since rules are processed in top down order, a rule can be hidden $($not evaluated$)$ if a higher order rule overshadows it$.$

d$.$

Rule shadowing is common on firewalls to offer multiple layers of protection.