A linear equation will have one unique solution when. . . A the coefficients of x are the same, but the constants are different

B the coefficients of x are different and so are the constants

C the coefficients are the same and so are the constants

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $36.98. find the probability that a randomly selected bill will have an amount greater than $173, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?