Fill in the blank with the most suitable word from the options given below :-
In accordance with the advice of a doctor, she is -------a diet.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → on
Be on a diet is a fixed expression meaning to eat only certain food, following a plan, for health or to lose weight. She follows the plan her doctor advised, so she is on a diet.
Example: My father has been on a low-sugar diet since his check-up.
Complete sentence: In accordance with the advice of a doctor, she is on a diet.
Why the Other Options are Incorrect?
Option 2: at — Incorrect. At shows a point in place or time; "at a diet" is not used.
Example: We met at the station.
Option 3: off — Incorrect. Off shows removal or stopping; it would suggest she has stopped the diet, against the doctor's advice.
Example: He took off his coat.
Option 4: in — Incorrect. In shows position inside something; "in a diet" is not the fixed expression.
Example: The keys are in the drawer.
Contrast: on a diet means following it; "off" would suggest she has stopped the diet.