Question about element conversion

‘Colossal defender’ shield has ‘100% Physical Damage converted to Fire Damage to Aegis of Menhir’ modifier.

aegis of menhir has following damage sources:

a. shield damage

b. flat damage bonus from aegis of menhir itself(physics and fire)

c. retilation damage bonus from ‘reprisal’ skill

and then, colossal defender changes physical damage from b only
or all of physical damage from a,b,c?

I’m not sure about this.

All physical damage that skill does.

A and B. Really just any general Physical damage on the skill or added to it (such as the Physical damage on Safeguard).

Only exception is Physical Retaliation damage. As far as I know, Retaliation damage isn’t converted by skill modifiers, just global conversion.