several patient serum samples were sent to the diagnostic lab for measles testing. the lab uses an indirect elisa method to detect anti-measles igm. the detection antibody is attached to an enzyme that converts a colorless fluid into a blue precipitate. for each sample, three identical replicates were performed in rows a, b, and c. based on your observations of elisa plates 1 and 2, which patients definitively have measles? (nclex style)