When I asked the driver/ to come with me to the temple/ he had been reluctant./ No error.
I think instead of 'had been', there should be 'was'. Even the answer key points that the error is in the 'he had been reluctant' part. But I am not sure why exactly is 'had been' wrong.
If we replace the first part with 'when I had asked the driver', would that make 'had been' in the third part correct?