Two Sets of 95% Confidence Intervals Correspond to Proportions Calculated

Multiple Choice

Two sets of 95% confidence intervals correspond to proportions calculated from a random sample of two groups: group A: c.i. = 0.64 ± 0.06; group B: c.i. = 0.61 ± 0.05. Which of the following could we conclude about the proportion differences of the groups with these confidence intervals?

A) There is definitely no significant difference between the groups at alpha = 0.05.
B) There is likely no significant difference between the groups at alpha = 0.05, but a formal hypothesis test should still be conducted to make sure.
C) There is definitely a significant difference between the groups at alpha = 0.05.
D) An error has been made; confidence intervals cannot be calculated for proportions.