GMAT Sentence Correction (SC) | A middleweight black hole weighs in at roughly 500 solar mas

hi abhi

here could you please tell me that after 2nd clause (,but) what is the subject here , means as you have told me that comma+SANAM pronoun is used when we have separate Independent clauses then what is the subject in that clause i think in the correct option C there should be subject .

please clarify , i am totally confused

thanks