She, like her brothers, ____ a doctor.

Concept: A finite verb must agree in number and person with its subject. When a subject is followed by a phrase introduced by words like "as well as", "along with", "together with", "with", "besides", or "like" and that phrase is set off by commas, the phrase is a non-essential interrupter — it does NOT add to the subject and does NOT change the subject’s number. Only "and" creates a true compound (plural) subject.

Application: The subject of this sentence is "She" — third-person singular. The phrase "like her brothers" is set off by commas and begins with "like" (not "and"), so it is an interrupting phrase, not part of a compound subject. The verb must therefore stay singular and present tense to match "She", giving "is".

Cross-check: Strip out the interrupting phrase and read the bare sentence — "She ___ a doctor" — which unmistakably needs "is". Contrast this with a genuine compound subject joined by "and": "She and her brothers are doctors" would correctly take "are". Since the phrase here is introduced by "like", not "and", the subject remains singular, confirming "is".

Where the other options go wrong:

• "are": treats the subject as plural, as if "her brothers" were joined to "She" by "and" — but "like" introduces an interrupter, not a compound subject.

• "were": is both plural AND past tense — it fails on subject number the same way "are" does, and also shifts the tense away from the sentence’s present-tense context.

• "am": is the first-person singular form used only with "I" — it never pairs with a third-person subject such as "She".