Ever since the death of his mother, my friend is utterly forlorn and wretched.

Answer: Option B

Frustrated : feeling or expressing distress and annoyance resulting from an inability to change or achieve something.
Lonely : without companions; solitary.
Fearful : feeling or showing fear or anxiety.
Gloomy : dark or poorly lit, especially so as to appear depressing or frightening.
Forlorn : pitifully sad and abandoned or lonely.

Synonym of Forlorn is Lonely