Your mother has commented on how little time your older sister, who recently married, spends on housework, as compared to what she herself used to spend when she was a newlywed. Your mother's comment reflects how gender roles:
a. vary By culture
b. Vary over time
c. are learned
d. are biologically determined

b. Vary over time        

Explanation:

Gender roles: In social psychology, the term gender roles are defined as the various values, attitudes, and behaviors that are being set-up by a society that the society considers suitable for female as well as male. However, earlier or traditionally, women and men used to perform entirely opposite roles, where women were considered as the caretakers of the family as well as the home whereas men are considered as the provider of the given family.

In the question above, the given statement signifies gender roles vary over time.

answer; critical thinking;

answerinteraction with others;