In a school laboratory, tools are placed opposite to their sequence of use. Students repeatedly cross their hands to take items. What is the main ergonomic problem?

Correct answer: Poor arrangement of use sequence and reach zone

The direct answer is B: poor arrangement of the use sequence and reach zone. In ergonomics, objects should be placed according to the order and frequency of use, with commonly used items within a comfortable reach area. If tools are arranged opposite to their sequence, students repeatedly cross their hands and make unnecessary movements. This can increase time, awkward posture, fatigue, and the chance of dropping or mishandling an item. Option A is wrong because colour does not explain the crossing movement. Option B is correct because it identifies both problems: wrong sequence and poor reach arrangement. Option C is irrelevant; interest is not the workplace-design problem described. Option D is irrelevant because the class name has no effect on tool access. A better layout places the first-used tool first and frequently used tools close to the user. Exam cue: repeated stretching, crossing, or searching usually signals a layout problem.