Ergonomics testing (or HCI testing) encompasses both user friendliness (ease of use, intuitiveness) AND whether important information is presented comprehensibly. Option A covers user friendliness, Option B covers information comprehensibility. Since ergonomics testing includes BOTH aspects, 'A and B' is the correct answer. Only A (Option C) is incomplete, and individual options A or B capture only half of what ergonomics testing evaluates.