The mean water temperature downstream from a discharge pipe at a power plant cooling tower should be no more than 100∘F. Past experience has indicated that the standard deviation of temperature is 2∘F. The water temperature is measured on nine randomly chosen days, and the average temperature is found to be 98∘F. The acceptance region in terms of the sample mean when a=0.05 a. x>101.09 b. xˉ≤1.645 axˉ≤101,09 d. x>1.645