8. (2 marks) In addition to studying how fast an emerging infectious disease spreads among people, John looked into how the Pollution Standard Index of a city, P, affects the lifetime of the pathogen causing such disease. Let L denote the duration for which such pathogen can survive in air. John suggested that the relationship between L and P was given by dL (5 -1) (P -200) dP 1000 where L is measured in minutes. John observed that, when P = 100, the concerned pathogen could survive for 6 minutes in air (i.e. L = 6 in such case). According to this model of John, for how long (correct to 3 significant figures) would this pathogen survive in air when P = 150? (A) 1.39 minutes (B) 7.92 minutes