Assume that we want to construct a confidence interval. Do one + of the following, as appropriate: (a) find the critical value to/2, 407 (b) find the critical value za/2, or (c) state that neither the 30- normal distribution nor the t distribution applies. Frequency 20- The confidence level is 90%, o is not known, and the histogram 10- of 51 player salaries (in thousands of dollars) of football players 0 - on a team is as shown. 0 4000 8000 12000 16000 20000 Salary (thousands of dollars) . . . Select the correct choice below and, if necessary, fill in the answer box to complete your choice. OA. ta/2= (Round to two decimal places as needed.) O B. Za/2 = (Round to two decimal places as needed.) O C. Neither the normal distribution nor the t distribution applies