The correct option is B depression
An abstract noun is a noun that cannot be seen or touched. It is an idea, quality or state.
From the options, 'depression' is a noun that refers to a feeling of severe dejection or sorrow. Hence it's an abstract noun and option B is correct.
'He' is a pronoun that refers to a person, hence it isn't an abstract noun and option A is incorrect.
'Dog' is a concrete noun; it refers to a living being that can be seen and touched. Hence option C is incorrect.
'Passed away' is a verb phrase, that expresses an action pertaining to death. Hence option D is incorrect.