Capitalization and Punctuation in Dialogue Situations

Hi all. Wondering about how best to punctuate and capitalize dialogue, specifically when a question mark or exclamation mark are used, and more specifically when the dialogue tag occurs in the middle of the dialogue. Examples:

A. "What do you think you're doing?" she screamed, "going over to his place without telling me!"

B. "What do you think you're doing," she screamed, "going over to his place without telling me!"

C. "What do you think you're doing?" she screamed. "Going over to his place without telling me!"

I'm wondering if it's okay to use a question mark in the first part, followed by a comma after the dialogue tag, and a lower-case first word in the second part (example "A"). When I'm writing, it feels like that's what I should do emotion-wise, but I'm not sure it looks quite right.

Example B seems to be punctuated perfectly, except that the comma before "she screamed" seems inappropriately mild for the heat of the comment (seems to me it needs an exclamation point, or at least a question mark).

Example C also seems correct as far as punctuation, but I don't really want to split the comment into two full-stop sentences (but perhaps I need to?).

What are the rules in this case? Thanks in advance for your help!