"They have called the police."
Translation:Ellos han llamado a la policía.
This is not the 'personal a':
When llamar means 'to call' it is transitive and requires an object - and in this case the direct object will be introduced by 'a'.
Llama a la estacíon de bomberos.
But there is a bit of a grey area here because llamar when it means 'to telephone' (also to knock, ring etc) is intransitive that doesn't have direct object and therefore no 'a' is needed.
llama un taxi or llama a un taxi are both acceptable
- Kiwi girl (forum)
Do you really need the personal 'a' in this answer?? It says that the solution is "Ellas han llamado a la policía", and that "Ellas han llamado la policía." is incorrect. I'm assuming that the speaker is not personally involved with the police....possible, but not something you would know from the context.