A company claims that 70% of its customers are satisfied with their service. A consumer group surveys 200 randomly selected customers and finds that 120 are satisfied. To test the company's claim at the 5% significance level using a normal approximation, the test statistic is calculated. Given that the mean of the binomial distribution is 140 and the variance is 42, which of the following represents the correct calculation for the test statistic, Z, after applying continuity correction?