She has visited her grandparents, ___? Select one:
a. hasn't she
b. has she
c. doesn't she
d. does she

a. hasn't she

Explanation:

Present perfect with negative tags

Tag questions (or question tags) turn a statement into a question. They are often used for checking information that we think we know is true.

Tag questions are made using an auxiliary verb (for example: be or have) and a subject pronoun (for example: I, you, she). Negative question tags are usually contracted: It's warm today, isn't it (not 'is it not')

Usually if the main clause is positive, the question tag is negative, and if the main clause is negative, it's positive. For example: It's cold (positive), isn't it (negative)? And: It isn't cold (negative), is it (positive)?

If the main clause has an auxiliary verb in it, you use the same verb in the tag question. If there is no auxiliary verb (in the present simple and past simple) use do / does / did (just like when you make a normal question).

There is one weird exception: the question tag after I am is aren't I.

For example: I'm in charge of the food, aren't I?

it would be d because the however is more proper and the comma is placed in the right spot