The correct option is B Plumber
The word for the phrase ''a workman who fits and repairs pipes'' is Option C, Plumber. Option A , 'Mechanic' is a skilled worker who repairs and maintains vehicle machinery. Option B 'Blacksmith' is a person who repairs iron objects and horseshoes. Option D 'Technocrat' is an expert in science and technology and has important position in government or industry. Thus, options A, B and D are incorrect and the correct option is Option C, 'Plumber'.