The classic side effect of anthracyclines is dilated cardiomyopathy. This question could have gotten tricky if you thought the pulmonary symptoms were due to the drug which could have led you to bleomycin (causes pulmonary fibrosis) but these pulmonary symptoms were most likely a result of dilated cardiomyopathy leading to HF and pulmonary edema.

Doxorubicin = Cardiac problems Bleomycin = Pulmonary problems One hint to tell that it's cardiac and not pulmonary is the BILATERAL crackles/effusions since blood is backing up it would affect both lungs while Bleomycin could present as unilateral. Main though thing is the S3 which makes it automatically cardiac-related (dilated cardiomyopathy) and not pulmonary so the answer is doxorubicin.