Impact of a C+ grade in a graduate course
One bad mark is unlikely to have much if any effect. Especially if it isn't the most recent. People are looking for indicators of success, so you have to provide plenty of that in your admissions package. Someone may ask you why you got a poor grade, but most will accept a reasonable answer. But your record is what it is and you can't change the past. Apply to the programs that interest you and make your best case.