18. Pick the sentence whose meaning is closest to the meaning of the underlined expression in paragraph 6, “Theindustrial-strength vibration that gives you that sought after “upbeat” feeling is stressful for the body.”
(A) The strength of the vibration is natural.
(B) The vibration is extremely strong.
(C) A vibration of that strength only occurs on industrial sites.
(D) A strength of the vibration can only be achieved in industrial cities.