Select the correct statement.

• a.)The critical z-score for a two-sided test at a 4% significance level is 1.75.
• b.)The critical z-score for a two-sided test at a 20% significance level is 0.85.
• c.)The critical z-score for a right-tailed test at a 9% significance level is 1.34.
• d.)The critical z-score for a left-tailed test at a 12% significance level is -0.45.