Which food item should the parents understand is the highest risk in younger children?

The correct answer is B: Cut-up grapes. Grapes pose a high choking hazard due to their size, shape, and slippery skin, especially for younger children. When children bite into whole grapes, they can easily get lodged in their throats, leading to choking incidents. It is crucial for parents to cut grapes into smaller pieces to reduce this risk. Small pieces of banana (A), baked potato (C), and cut-up pieces of steak (D) are generally safer food choices for children as they are easier to chew and swallow.