Which of the following foods is likely to be consumed by a lacto-vegetarian?

A lacto-vegetarian diet includes dairy products but excludes meat, fish, and eggs. This means that individuals following a lacto-vegetarian diet can enjoy foods that contain milk and cheese, as these are key components of their dietary preferences.

The grilled cheese sandwich is a suitable choice for a lacto-vegetarian, as it is made with bread and cheese, both of which are acceptable in this diet. The presence of cheese provides a source of protein and calcium, making it a nutritious option for someone who avoids meat and fish.

In contrast, the other options contain animal products that are not allowed in a lacto-vegetarian diet. Scrambled eggs, tuna fish salad, and hamburgers all include either meat or eggs, which are excluded by those adhering to lacto-vegetarian principles. This distinction highlights why the grilled cheese sandwich is the correct answer for a lacto-vegetarian's consumption.