In a test of H0 : p = 0.4 against Ha : p ≠ 0.4, a random sample of 100 yields a test statistic of z = 1.28. The p-value for this test is approximately equal to which of the following:
(a) 0.90
(b) 0.40
(c) 0.05
(d) 0.20
(e) 0.10