Step 1: Identify the auxiliary verb.
The sentence She is a lawyer uses is as the linking verb. This forms the basis of the question tag.
Step 2: Apply the question tag rule.
For affirmative sentences, the question tag is negative. Since the sentence uses is, the tag becomes is not, contracted to isn't. The subject pronoun remains she.
Step 3: Confirm the answer.
She is a lawyer, isn't she? is the correct form. Options using does or doesn't are wrong since there is no action verb in the original sentence.
\[ \boxed{\text{isn't she}} \]