Why do you get up so early in the morning, Tracy?
I generally make it a _______ to be up by 7 to read English.
A plan B wish C secret D rule
I think the correct answer is A, or D. But the correct answer given in the book is D. I can't understand.
The phrase "I make it a rule to..." means that you try to do something consistently or as a habit. "I make it a rule to drink plenty of milk", "I make it a rule to respect my elders". I think it often has a sense of being motivated by a principle rather than just being a "plan", although that doesn't always apply. In the example you give I would choose "rule", but "plan" would not be out of place.
not a teacher
Student or Learner