B) An action which lasted for some time in the past and its result was also visible in the past

- At last the bus came. I’d been waiting for 20 minutes.

- She was tired. (Why? Because) - She had been working hard all day yesterday. (Compare this situation with the Present Perfect Continuous: She is tired. She has been working hard all day.)

- She was wet. (Why? Because) - She had been walking in the rain. (Compare: She is wet. She has been walking in the rain.)