as if he (was, had been) a doctor

[keannu]

This is a queston of my grammar book.
The answer here is "had been", which means that "had been" denotes counterfactual hypothesis in as if clause, but from teachers here, I learned "had been" doesn't give a definite answer for being true or false. What do you think?

A : He talks as if he (was, had been) a doctor.
B : In fact, he was a nurse.

 

[keannu]

Is "had been" the only answer here?

A : He talks as if he (was, had been) a doctor.
B : In fact, he was a nurse.

 

[Rover_KE]

'He talks as if he was (or 'were') a doctor' is acceptable to me.

Rover