The Authority of Pollution Control sets the permissible level of CO2 emmissions to 10mg/l. If for Calibration, GM sets the permissible level to 5mg/l, what will be the worst passing and best failing values in this case, respectively?

GM sets calibration to 5mg/l. Worst passing value would be 5 + 10% of 5 = 5.5mg/l (at the upper edge of passing). Best failing value would be just above 5.5mg/l. But wait, the question mentions the Authority sets 10mg/l as permissible. Re-reading: if calibration is 5mg/l, and we need to find worst passing and best failing values relative to the calibration standard... With 10% tolerance: passing range is 4.5-5.5mg/l. Worst passing = 5.5mg/l. But that's not in the options. Let me reconsider... Ah, maybe the question is asking about values relative to the Authority's 10mg/l limit? If GM sets 5mg/l internally, and Authority allows 10mg/l, then worst passing at Authority level could be 9mg/l (still under 10), and best failing could be 11-12mg/l (above 10). The option shows 9, 12 which means: 9mg/l passes (under 10mg/l Authority limit), 12mg/l fails (above 10mg/l). This interpretation makes sense.