Final answer:
A lacto-vegetarian would likely consume a grilled cheese sandwich, as their diet includes dairy products but not meat, fish, or eggs.
Step-by-step explanation:
The food likely to be consumed by a lacto-vegetarian is D. Grilled cheese sandwich. Lacto-vegetarians include dairy products in their diet but abstain from eating meat, fish, and eggs. Therefore, options A (Scrambled eggs), B (Tuna fish salad), and C (Hamburger) are not suitable for a lacto-vegetarian as they contain eggs, fish, and meat respectively.