B, Tan believes that nonstandard English can be an important part of family culture.
Explanation:
In the text, Tan states that "[nonstandard English] has become our language of intimacy, a different sort of English that relates to family talk, the language I grew up with." Because Tan refers to nonstandard English as her and her husband's "language of intimacy," she indicates that it is an important part of their family intimacy.
