For a lower tail test, the test statistic z is determined to be zero.The p-value for this test is

A) zero.
B) -.5.
C) +.5.
D) 1.

For a lower tail test, if the test statistic z is determined to be zero, it means the observed value is exactly equal to the mean under the null hypothesis. The p-value in this case represents the probability of observing a test statistic as extreme or more extreme (in the direction of the alternative hypothesis) than the observed test statistic. Since z=0 is at the mean (the center of the distribution), the p-value is the probability of observing a value less than or equal to the mean, which is 0.5 or 50% of the distribution.