My father was passionate about two things: education and socialism. He was himself a born teacher. Indeed, he could never restrain himself from teaching, and as a small boy I was frequently embarrassed by his desire to instruct everybody - people in railway carriages, for instance - though I realized even then that it was an innocent desire, quite free from vanity. He was equally ready to receive instruction. Education, to men of his generation and temperament, was something it has largely ceased to be nowadays. It was the great golden gateway to the enchanted realms of the mind.
The author wants us to know that his father

Options

A. was a school teacher
B. was an educationist and socialist
C. used to travel a lot
D. loved teaching